Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)
 Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

Protect your investment in diesel power and confidently extend drain intervals with our top-grade synthetic diesel oil. AMSOIL Signature Series Max-Duty Synthetic Diesel Oil delivers 6X better wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222. Advanced synthetic technology provides excellent viscosity control and outstanding extreme-temperature performance, while minimizing oil consumption. The result: protection that’s boosted to the max.

Package sizes include:

Quart Bottles
Gallon Bottles
2.5-Gallon Bottles
30-Gallon Drum
55-Gallon Drum
275-Gallon Tote

Product Code: DEO • Brand: AMSOIL




MSDS Data Sheet

Product Details Tech Data Reviews & RatingRelated Videos

Product Applications
Use in diesel engines and, where appropriate, gasoline engines requiring any of the following specifications:

Product Application Specs

• API CK-4/SN, CJ-4, CI-4+, CF
• Volvo VDS4.5, VDS4, VDS3
• Mack EOS-4.5, EO-O
• Renault RLD-4, RLD-3
• Cummins CES20086, CES20081
• Caterpillar ECF-2, ECF-3, ECF-1-a
• DDC 93K218, 93K215, 93K214
• DFS 93K222
• ACEA E9, E7
• MB 228.31
• MAN 3575
• MTU Type 2.1, II, I
• JASO DH-2
• Allison TES439
• Deutz DQC III-10LA
• Scania LA-2
• Chrysler MS 10902
• Ford WSS-M2C171-F1

Product Description
Maximum Engine Protection: Wear on rings and cylinder liners leads to increased oil consumption and loss of compression, resulting in reduced horsepower and fuel economy. Independent testing shows AMSOIL Signature Series Max-Duty delivers 6X more wear protection than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222, delivering the security of providing your diesel the extra protection it deserves.

Viscosity Control
Using top-tier synthetic base oils, AMSOIL Signature Series Max-Duty is naturally resistant to oxidation and the thickening effects of soot contamination. That, along with boosted detergent/dispersant additives, keeps soot particles suspended independently, helping prevent the formation of larger, wear-causing particles. Viscosity increase is minimized and soot-related wear is controlled. Lower volatility also helps Signature Series Max-Duty retain its viscosity after high-temperature service for maximum engine protection and efficiency.

Excels in Extreme Temperatures
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil resists thermal (heat) breakdown better than conventional and competing synthetic diesel oils. Unlike conventional oils, Signature Series contains no wax, staying fluid in sub-zero temperatures for easier starting, improved oil flow and reduced wear. Signature Series 0W-40 (DZF) has a broad viscosity range that offers 4X better cold-cranking ability than a 15W-40, making it excellent for use in both hot-operating engines and cold-weather starting extremes.

diesel oil Scuffing Test

Minimizes Oil Consumption
AMSOIL Signature Series Max-Duty has a low rate of volatility (burn-off), reducing oil consumption during operation and passing less oil vapor into the combustion chamber. It provides up to 76 percent less oil consumption than required by the API CK-4 standard in the Caterpillar-1N oil consumption test.

diesel Oil Consumption

COMPATIBILITY
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil is compatible with other conventional and synthetic engine oils. Mixing AMSOIL diesel oils with other oils, however, will shorten the oil’s life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL synthetic diesel oils.

diesel oil OfficialOil icon

SERVICE LIFE
Diesel Engine Service Life

Heavy-Duty On-/Off-Road: Three times (3X) OEM1 recommendation, not to exceed 60,000 miles/600 hours or one year, whichever comes first.

Turbodiesel Pickup: Two times (2X) OEM1 recommendation, not to exceed 25,000 miles or one year, whichever comes first.

Gasoline Engine Service Life

Two times (2X) OEM1 recommendation, not to exceed 15,000 miles or one year, whichever comes first.

Drain intervals may be extended further with oil analysis.

Refer to your owner’s manual for OEM drain interval recommendations and guidelines for severe and normal service.

Note: Extended drain intervals are not recommended for performance-modified engines, when using biofuels containing more than 10 percent ethanol or 15 percent biodiesel (B15) or for 2007-2009 Caterpillar* C13 and C15 on-highway engines. Extend drain intervals beyond OEM recommendations in these instances only with oil analysis. Note: 2007-2010 Dodge**, Ford** and GM** turbodiesel pickups are also not recommended for extended drain intervals when using DHD.

HEALTH & SAFETY
This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Material Safety Data Sheet (MSDS).

Click here to view the MSDS Data Sheet for AMSOIL DEO.

Keep out of the reach of children. Don't pollute. Return used oil to collection centers.

TYPICAL TECHNICAL PROPERTIES
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil (DEO)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445)15.4
Kinematic Viscosity @ 40°C, cSt (ASTM D-445)94.5
Viscosity Index (ASTM D-2270)173
CCS Viscosity @ -30°C, cP (ASTM D-5293)5555
Pour Point °C (°F) (ASTM D-97)-43 (-45)
NOACK Volatility, % weight loss (g/100g) (ASTM D5800)9.2
Total Base Number (ASTM D2896)10.1
High-Temperature/High-Shear Viscosity, cP (ASTM D5481)4.3
Sulfated Ash Content, wt. % 0.99

6x More Wear Protection than Required!

Understanding the 2017 FA4 and CK4 Diesel Oil Specifications

Diesel Power Challenge

Did this product meet your expectations?

(click on a star to rate)
Product Name: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)
Current Rating: 4.88 out of 5 stars
Total Votes: 199 vote(s)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Vegadriver: space

Great oil

Run this oil in my 2012 Duramax. Can go a full year without oil change. Saves me money. Also use the Amsoil filter.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by JasonV: space

EcoDiesel oil for my truck

Love it.
Good quality oil for a good price for this quality oil.
Will Definitely buy again as its cheaper to do it my self than having the dealer do it and I get a way better oil for my truck.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by NYMustang50: space

Great Product

Stuff is worth every penny. Oil analysis test prove it. Always use Amsoil in all my personal engines.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by PAPPY: space

BEEN USING IN MY 2007 GMC

ALSO IN MY SS2 CAMARO

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by DWS: space

All I use

Been using Amsoil diesel oil and Ea08 filters every 15k since the truck turned 30k miles. Have 276k now.
Could do a longer interval with testing

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ron: space

Max Duty 15w-40 Diesel Oil = Good Stuff

I am relatively new to Amsoil but have and have both Duramax and Cummins - currently have a L5P Duramax with an Amsoil Duel Bypass oil filter set up which I did not have on my previous Duramax. Thus, apples to apples may not be in the following:

1. Blackstone reports come back much better than with the Rotella T-6 I was using in the prior '15 Duramax actually with about 7500 vs 5000 miles.
I got some usage w/Rotella T6.

2. A bit of oil usage with the Rotella t-6 but absolutely none with the Amsoil.

Repeat not apples to apples exactly as different engines and the L%P has a duel bypass set up on it.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by BRIANS cummins: space

AMZING STUFF 429,000 miles

I use the 5w40 and 15w40 in my 2003 Dodge Ram 2500 5.9 cummins ... when I got the truck it had 378,000 also had little blow-by.. it ran mobile 1 most of its life .. switched to AMSOIL signature series (max-duty) and the blow-by was gone and it also slowed down completely with drinking some oil .. 7-10,000 and I might need to add 1/2 qt this stuff is AWESOME .. now I have 429,000 and this cummins runs like its NEW with 10,000 miles on it .. everyone that I know with a cummins , I get them hocked on it also .. everything I own has AMSOIL

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mark: space

I've used Amsoil for over 20 yrs.

I've used Amsoil in my last 5 class 8 trucks. Absolutely no problems. Why on Earth change. Use Sig. 5w-30 in my Ecoboost too

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Reg Moody: space

I use Amsoil exclusively

Used in all my vehicles for years

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike: space

Diy

Maintenance

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Dogman: space

I have used Amsoil products for years and will continue to.

I use this oil in my '02 2500 Ram Diesel to protect that engine for the long haul. The 5.9L Cummins is the last of the "loud ones" for Dodge. I want to try for 750,000 to 1 million miles before it needs any real work put into it. That sound is one of the reasons that I bought it in the first placeI love how it runs and I get great longevity out of the oil. If you run a diesel you would be crazy to not try some in yours. Worth every penny!

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by rdj519: space

2010 gmc Diesel truck

I installed the bypass oil filter system when I bought it new. Oil sample every 7000 miles. This oil and system is the best thing I have ever done for my big truck. Only the best for my baby

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jack: space

Too Early to Tell

I have always run synthetic oil in everything, but since I bought my Duramax, I thought I'd try you product and filter. So far so good, I'll let you know in about 150000 miles.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by obg: space

oil

Great stuff wouldn't use anything else.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by REJ: space

I will buy this product again

This is the only product that I can find that is recommended for my Eco Diesel and it performs as advertised.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike, 2017 Dodge Ecodiesel: space

Solid Amsoil User

First time have used Amsoil diesel oil. So far so good. However I didn't notice much change in fuel economy after using Amsoil 5W40 SS diesel oil for my first oil change in this truck, in town driving. High way driving did show some improvement, all the way up to 30.2 mpg, previously had gotten 29 mpg. I think part of this is my motor is still breaking in as diesels take awhile to do so. Overall I am pleased & have used Amsoil in both of our vehicles going on 18 years.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Pinkpeaches10: space

I would always buy amsoil

Perfect oil.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Doc Pat: space

I always use this product on my diesel trucks.

I use this on my 3 diesel trucks. 1985, 1994 and 2001 F 350.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by JGD: space

Outstanding product!!

I am using this in my new F250 Diesel, as always Amsoil has created a superior product you can depend on. I can physically tell a difference just by using this oil. The truck runs so much better.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jonathan: space

Awesome stuff

I am rough on my trucks farm use hauling ext... Has 300k+ doesn't lose it burn a drop still run 25k between oil changes love my amsoil

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Russell: space

The only oil

I was told it was it would help eliminate dust particles from the DEF system that build-up in an engine. It has helped with eliminate dust buildup in the engine significantly. Immediately after using the first time, many miles ago, I felt more power being produced from my engine. I'm a very satisfied customer.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Butch: space

I use Amsoil in all my vehicles.

I have used Amsoil for 20 years. I like the extended oil change intervals, it saves me money and doesn't damage my equipment. I took oil samples and had them tested after 18,000 miles. They came back no wear and more mileage before changing. This was on a 1978 Dodge van with 180,000 miles. I currently use Amsoil in my 2006 Ford F350 6.0 diesel FX4 in all gear boxes, and 2012 Ford fusion. I am very satisfied with Amsoil performance.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Joe: space

Have used Amsoil for 20 years.

I use Amsoil in every combustion engine that I own. Vehicle, farm equipment, lawn mowers welding machine and generator. Never had a lubrication issue with any of them.
Best oil on the market hands down!

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Scott: space

Synthetics

I believe in synthetics and Amsoil.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Doug: space

I will keep buying this product

love this product, but have nothing to compare it to because the last two new trucks I've purchased i change the motor oil and transmission fluid as soon as i get home. sold my 2007 GMC Classic Duramax 4X4 with 180,000 miles for over book price. To a mechanic. i could go farther but always change oil at 5,000

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jason: space

I will purchase this again and again.

I use this product in a 3/4 ton work truck.
Very high quality product.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Grandpy: space

Great

No worries

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Super04FX4: space

Best Diesel oil on the market

After trying several different synthetic diesel oils over the years...I have settle on AMSOIL as the best. I see consistently better cold starts and the extended change interval is a huge plus!

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ray: space

I use Amsoil prod in all my vehicles.

I have used Amsoil 5w- 40 since I purchased my truck 8 years and 210,000 miles ago. The truck runs as good today as it did then.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by GregM784: space

Amsoil & Cummins

Runs great, runs cooler, a product you can trust.

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Tom: space

Over 25 yrs using AMSOIL...

I'm sold! I've used Amsoil products in all my vehicles for over 25 years. Engines run more quiet/smooth, better fuel mileage, and longer engine life. I recently convinced a friend to try Amsoil, they had an immediate 4-5 mph increase! What more can i say?!!

Item Reviewed: Premium Diesel Oils (DEO,DME)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mud Creek Ranch: space

I do buy this product again and again

Love this product, use it in both of my diesel vehicles religiously! Use it in my MF 300 Dozer as well, use Amsoil in my gas engines as well on the ranch.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by G513: space

Pricey

Really haven't noticed any real benefit over cheaper options. The cost is a major problem.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by James: space

Amazing product

This amsoil does wonder's with my 2010 6.4 F250

Didn't change my oil tell 14k miles had an oil analyze at black labs came back great they said it looked better them most 6.4 diesel at 5k miles and told me they couldn't wait tell another 14k miles to see what it looks like

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Matt Z.: space

Always improving fuel economy

I have been using Amsoil in this truck since I purchased it, it turned 210,000 miles. I have averaged 17.9 mpg over the life of the truck. It has regularly towed 17k plus. These fluids are spot on!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Gregory: space

Great

I switched to this oil from 5w/30 Series 3000
Because of price.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 7Trumpets 42: space

Fabulous lubrication

I am having regular oil analysis with each 10K mile change. Engine metals are lower than average for the V-M 3. 0. I couldn't be happier with this signature Amsoil product!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Hauss: space

Top Performer

I've been using Amsoil lubricants for decades. I'm loyal to the brand. I've been with Amsoil through the good times, and one of their bad times (back in the eighties). I've run Amsoil in motorcycles, cars, trucks, boats, high-performance engines, and factory daily drivers. I have extensive experience in engine machining/building, and I've seen, first hand, how Amsoil provides performance and durability to engines that push their design limits.

Recently I bought a 2017 F250 with the PowerStroke diesel, and I got to reading about the particulate filters, and how oils not approved by Ford could cause premature clogging of the DPF, and possibly void the manufacturers warranty. Oils manufactured to the CK-4 spec initially resulted in premature wear in 2017 PowerStroke engines, so Ford released their own specification, WSS-M2C171-F1, and instructed owners to run CJ-4 oils until approved CK-4's were available. Since then several products have been approved by Ford for use in PowerStrokes, but concerned about the performance of the available CK-4 oils, and curious about how Amsoil's Signature Series Max-Duty Diesel Engine Oil compared to them, I submitted a couple of samples to the guy who runs the 540 RAT Blog for testing. The Amsoil product tested superior to all others tested to date, beat only by another of Amsoil's own CI-4 spec diesel engine oil. I wasn't surprised by that, based on my experience, but I was surprised to see a conventional CK-4 oil approved by Ford that also meets WSS-M2C171-F1, performed as well as Amsoil's Sig Series Max-Duty, and costs about half what Amsoil's product does. I would love for Amsoil to explain why their product is still superior to that competing product, even though they performed so similarly in 540 Rat's test. At thirteen quarts, half the price is quite a savings. Is it really worth the price?

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Rock: space

I am going to continue to buy this product

This product is great. I have ran this product the last 15,000 miles. My trucks starts smooth after sitting for a week in the cold weather of northern NM. Never misses a beat either. Would recommend to any diesel owner out there.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by RAV: space

Consistently Reliable

Since 2010 I've been using Amsoil fluids and filters in my Dodge Ram 2500 Cummins Diesel and as a result, have had no engine or transmission failures.

The diesel engine oil & filter are both 25,000 mile change frequency; Amsoil does cost more, but you'll save money in the long run with zero failures and extended periods between scheduled maintenance.

I also ran Amsoil transmission fluid in the same truck for 70,000+ miles with no slippage, and always witness iyuyreliable, positively locked shifts.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bam Bam: space

I will buy again and always looking for better with Amsoil

I drive 114 miles a day for work

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Bentley: space

I would buy again

Feels like my trtuck runs a lot smoother

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Pete: space

I will be purchasing again

Love using the best protection available for my Chevy 6.6 that I work hard everyday and with 123,000 not a single hiccup.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Chuck: space

I buy it all the time

I would and do buy it all the time

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Chuck: space

I would and do buy it all the rime

😉

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Dave: space

Great product

Engine ran cooler in summer by five degrees with Amsoil. -25C starts not an issue, even when I forgot to plug in.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Sky Pilot: space

Amsoil - Awesome oil products

I use the Signature Series Max-Duty Synthetic Diesel Oil 5W-40 in my 2004 Dodge Ram 2500 4x4. I following the recommended drain interval so I end up changing it out yearly before I reach the kilometer limit. I do mostly highway driving. I don't think I've ever had to top it up between changes either. Great cold weather starting properties for winters in Alberta.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Stan H.: space

I am a true believer

I have used amsoil for years in my 6.7 cummins diesel and it has never failed to deliver . I recently swithed to the new 6x signature 5W-40 and I noticed that my oil pressure went up one pound and my fuel mileage went up one mile per hour also . Now to some this may not be a big deal but it adds up over time and that it is giving me better pressure at the same time only goes toward helping to further protect my engine. with the increased wear protection quality and potential I look forward to many more years of faithful performance from amsoil oil just like this .

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Greg: space

Great oil for cold winter

I have used this oil in my Silverado Duramax in cold weather and it helps with cold starts and driveability during long warm-up time. The engine gets lubrication almost immediately upon startup and sounds like it is running on a summer day. Amsoil is the best!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Josh: space

Have purchased 5 years in a row

This is a high mileage truck 350,000 km it starts great in cold weather and a faster clean start

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Phil: space

Best Oil

I have used and only used Amsoil in my 2004 Dodge 2500 with the 5.9 HO Cummins. The wear protection and the oil life is amazing.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Airstreamer Joe: space

Gives you freedom to roam!

I have been using AMSOIL in my GM tow trucks sense 2000. I have out over 300,000 miles on 3 GM pickup trucks, while towing my 34' Airstream in all the lower 48 states, 2 summers in Alaska, and all but one Canadian Provence's.
I put a dual filter kit on my 2000 GMC 2500 gas truck, and switched to AMSOIL when it had 3000 miles on it. I set up an oil diagnosis program at a 3rd party lab. I setup a system of monitoring my oil every 3 months, but only changing it one time per year (usually about 20,000 miles mostly towing the 10,000 pound Airstream). I would change the full flow filter 2 times per year, and the bypass filter one time per year. I bib not get a recommendation to change the oil from the lab in 3 years. I had no problems with the engine in the 125,000 miles I put on it.
I traded the truck for a 2004 GMC 2500 diesel truck, and went through the same setup of the oil change system using AMSOIL Diesel oil. I put 122,000 miles on that truck, with no oil related problems. I sold the truck to a friend and bought a 2015 Chevy 3500 diesel truck, and you guessed it, it has the same oil system setup on it. It now has 30,000 miles with no problems to date. The 2004 truck I sold to my friend is still using AMSOIL, and changing it one time per year. It is still being used to tow a travel trailer, but I do not know how many miles it has on it now.
I would recommend AMSOIL and their Dual Filter System to anyone that puts tough miles on their truck every year.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike: space

this oil is really good

When I start my engine at -35 degres celcius it runs smoothly.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike: space

this oil is really good

When I start my engine at -35 degres celcius it runs smoothly.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike: space

I highly recommend this oil for extending your engine life

I switched my 2016 Ford 6.7 diesel oil @ 60K miles...with 126K on it now and driving 100K per year towing heavy loads"half the miles". I trust this engine oil above all others and expect to get at least 500K on the engine before I buy another one!!!!!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jamie: space

I will buy this again

This oil flows pretty good when the temperature gets down to zero.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Wild Bill: space

Just hit the 40K mark in a 2016 EcoDiesel. Only run the best

Just hit the 40K mark in a 2016 EcoDiesel. Only run the best oil and no worrys. Have used AmsOil in all my vehicles, boats, and ATVs for over 10 tens with NO engine problems.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Doubleplay7: space

I would buy this product again

This product is a good product that is good for a wide range of diesels. I run this in a 02 Ford F-250 and will be running it in a new Ram 2500.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Amsoil Believer: space

Only Amsoil Will Do

Simply put, Amsoil is the only product I will use on all my vehicles, if I can help it. Have been using Amsoil since my first FORD SVT LIGHTNING in 1993. I am using the diesel oils for my foreign vehicle, a Ford Everest, that's made in Asia. I have also used the diesel oil in my farm vehicles, a Dodge Ram 3500, and other diesel engines. You can't go wrong with AMSOIL.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Z: space

I will buy this oil again

Use in my tuned 2006 2500 Dodge Ram Laramie Mega Cab. Many miles and still runs like champ!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Eric: space

Oil works as advertised

I have been using Amsoil for a very long time. I love when they come out with enhancements like this new diesel oil. I will take all the protection I can't get.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Al: space

I will be buying this again for my grandson

My grandson uses this this in his dodge guide truck, he is a fishing and hunting guide in the Lake of the Woods Nestor Falls, Ontario area. He also use AMSOIL in his guide boat and I use AMSOIL in all of my vehicles including boats. I have been using AMSOIL products since about 1983 and as far as I am concerned there is nothing better. I recently changed my 2012 corvette from Mobil 1 to AMSOIL signature 0W-30.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Slick Nick: space

Great product

I'm using it for year in my semi and never left me down. Great quality lubricants.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ode: space

It's good stuff

I use this in my ram 1500 ecodiesel. It performs well. No usage with 49k miles.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Moparguy: space

Awesome

Awesome product. Long time amsoil user. The products just get better!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Greg: space

Great Products

The ONLY I will put in my '16 Ram 3500 Dorsal!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by $ilver6_7_cummins: space

Highly recommend

I started using Amsoil about a year and a half ago. It is now all I run. Wether it be in my diesel truck, snow mobile or boat, Amsoil has the product for it!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Kissoondath Rovin: space

Ase Master tech, L1

Arms oil products is great, the experience I had with the signature series oil I have used it on 2 of my 2016 &2017 , 6.7 diesel and they both have burnt the oil , I had to add oil A quart after driving 16000 miles , now I do all my oil change at 15000 miles to be on the safe side , the arms oil is a much durable oil compared to other oil it there I will continue using the heavy duty for marine diesel and gasoline oil

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Steve: space

This is the best diesel oil out there.

Excellent at every point.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by The real noble: space

Great product

Use Amsoil synthetics with bypass filtration in my 2012 Ram 3500 Cummims. Oil analysis has got me over 20,000 kms between oil changes. Highly recommended

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ray: space

I've always used Amsoil products in my 2007 Dodge

Always change my oil every 6 months. I have only 65K and mainly tow a 30 foot trailer in the summer months. I use Amsoil, engine oil, transmission fluid, differential oil, and filters. Great products.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ron: space

Great product!

I've been using Amsoil for 15 years now. Diesels, and family's automobiles, utvs, boats, and more. I know i can trust Amsoil, and have extended the life of all my equipment. Great oil, filters, and much more.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Fordfan: space

Will use again and again

excellent

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Cooory Ed: space

Amsoil 5w 50

Great oil
I run amsoil in everything

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Muleboy: space

Moving all my vehicles over to 100% synthetic

Swapped my Duramax diesel over to this oil. I want this vehicle to last for years so I am going to use the best oil I can. I plan on doing oil analysis as well to get the most out of this product.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Kyle: space

I only run this oil in my diesels

I have four dodge diesels and a cat powered welding machine and I run this oil year round with zero issues. I do oil changes every 25000kms.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Pat: space

I would buy this product again and again!

I use this oil in my 2014 Dodge Ram EcoDiesel. Amsoil updated the oil from 5W-40 to 10W-40 based on Dodge recommendations. Great oil.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jon Driver: space

Like 6x protection

Under heavy usage and need peace of mind

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Chris: space

Must be good

My engine is still running and since I can't see inside it, it must be working.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by SG: space

Noticeable difference

Dumped class 3 synthetic rosella t6 for a true synthetic class 4 PAO Amsoil Sig Series 5w-40. Turbo Diesel is running smoother, quieter, cooler and 2-3 mpg boost! Worth the money!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Rick Wysynski: space

So far so good

I was a Royal Purple junkie since it was the only synthetic available to me where I live and got it free. It worked great in my gas truck and other gas vehicles. I switched to Amsoil since I purchased a diesel truck and became a Preferred Customer. Really like that part !!!
The truck runs much better and accelerates better than the Ford oils that were in it and oil change at 25,000 miles is a nice $$ saving feature. I will switch to the new synthetic 5-40 on the next oil change and then extended changes past 25,000 would be nice. I monitor all things done to my truck and log it.
Put 9,000 mikes on the truck in less than 4 months and excellent results !!!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Phil in Tulsa: space

Signature Series Max-Duty Synthetic Diesel Oil 5W-40

I've been using AMSOIL heavy duty diesel oil for years and it has performed extremely well. This year I decided to try the Signature Series Max-Duty and was I amazed. I didn't believe I could tell the difference but the engine runs even smoother. I tow trailers with my truck and protecting the engine is paramount to reduce wear and lengthen the life and this oil delivers.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Kelley: space

Only oil I buy

I use this oil in my skid loaders as well as heavy duty pickups pulling heavy loads daily.
I have been sold for many years after I had 6.0 diesel that dumped all the oil and the only thing that saved the motor was this product.
All the shop had to replace was head gaskets

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by patrick: space

I would buy it again and use it for all my power equipment

In my Excursion Diesel 250,000 miles

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by F450: space

Not sure for the Fords...

First, I'll say that I love Amsoil. I run Amsoil in every engine/transmission/differential/etc I own. I'm not sure about this new oil. My oil temp in a Ford 6.7 Powerstroke usually runs about 203 degrees (previous version of Amsoil diesel oil). With this new oil (December it might have come out???) I'm running 7-10 degrees hotter on average. I'll probably try one more oil change with it and if it still runs hotter, I'll have to find another brand.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Dave: space

Extended oil life, runs cooler

I am astonished at the engine oil life provided by this oil, compared to the Mobil synthetic I used previously. I'm at 14000 km, 80% city, and the computer is telling me I still have 20% oil life. Previously I would get to about 10k and be looking to change. Admittedly I changed to Wix filter at the same time from Oem, so not a 100 % true comparison. Winter, with more idling, will be the real test. Engine seems to be running cooler even in 30C weather- that's hot for us!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Nimble: space

Great oil

Use it a 09 Chevy Duramax, starts great even if it hits 0 or below

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by John R: space

I would definitely buy this product again

I currently use this product on my 2016 Ram EcoDiesel with no issues and have use the previous 5W40 diesel product on previous diesel pick up trucks and heavy-duty equipment with no complaints. Thank you Amsoil.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Matt: space

Great product only oil for my Harley, period!

Engine ,primary and transmission fluid for my fxstdi.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by jobu: space

impressed

i have used Amsoil in the past in a 6.0 powerstroke and didn't really see much difference, tried it again in my 6.7 powerstroke and love it. The motor starts and runs smoother and helped with the mpg

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ryan: space

Great stuff

My son uses Amsoil in his 2011 Ford F350. He has many mods on his truck. This is the only oil that he trust.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Rob: space

Did what I was hoping it would do

I put this in my Kabota BX25
I was hoping it would quiet the motor and make for easy starting on cold inter days.
It did quite the motor a lot.
Started with no issues.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Big Frank: space

Great oil unbeatable

New 2017 ford diesel. Outstanding oil. Highly recommend it. Would only use this oil in my new Diesel engine It is so high tech

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by None: space

Great product

Ran for 8 thousand miles & love it so far

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Dimonic: space

Correct oil and filter, ready and waiting for pickup.

I like to do my own oil changes, and avoid all the "additional" services the dealer offers.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Cumminswitit: space

Love this stuff

My truck and I love this stuff. I run it for a year between changes and love it. Best oil out there

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by elkoholic: space

Will use this oil from now on.

Truck is used for hauling horses.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Petro: space

Trusting Ams Oil to take care of my truck

I use Ams oil in every application of my truck and never have I been let down

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by MURF: space

YES

IN A DODGE SPRINTER

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 4B RANCH: space

amsoil synthetic with EAO filters

I have three diesel trucks and five diesel tractors, and all are serviced with Amsoil products. Besides extended oil changes, my engines stay clean and trouble free. I would never consider using anything else.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Randy: space

I would buy again and have continued to buy this oil.

I have used this oil for over 18 years in a 7.3 diesel ford-350 4x4 and have had great performance in using it .The engine doesn't have to work as hard with Amsoil synthetic oil 5-40w it runs cooler and less RPMs for the same speed as other oils . If you're not using Amsoil synthetic oils in your engine and truck and or other motor vechicle your missing out on the best performance your motor Vechicles can give you ..

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by engr: space

l6x diesel oil

looks good. I will need more time to fully evaluate it.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by truckguy12: space

Great premium diesel oil IMO

Premium oil for a premium price. Works out in the long run for me with extended drain intervals. I use it in all my diesel business trucks.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Trev: space

Awesome product

I use amsoil in all my vehicles, even my lawn mower. This stuff is the bomb, less oil pressure due to better flow, and smother running etc...

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by J: space

Great oil for your engine

Great oil for you engine can't go wrong with full synthetic. Other then manufacture recommendation on oil brand this is the only other brand I use. I'm still old school so 5k oil intervals is cheap insurance for a $67k truck. Oil itself is amazing compared to previous oil used at 5k miles drains Amsoil looks and feels great. Smoother engine idle and smoother engine operation at higher rpm range. I have a digital psi gauge installed and with Amsoil the engine oil psi has maintained same psi throughout the oil intervals the oil temperatures has dropped 8 degrees lower under same driving conditions. I know that's not a professional oil analysis but it's what I've got.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Steve: space

I will definitely buy this oil again

I use amsoil in everything I own, from vintage snowmobiles to outboard motors to stihl concrete saws to my cummins to my jeep crd. I swear by your products and have switched a number of people over to it. It's cheap insurance especially when you plan on keeping your investments for a long time. It's the only oil I can count on

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by DWC521: space

Great product!

My 2016 F350 6.7L runs smoother on this oil

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Hurst: space

2016 Ram Eco Diesel

I notice a big difference in mileage and how the truck ran after changing the factory oil to Amsoil. The mileage is up over brand X that I replaced. I've used Amsoil in all my diesel trucks, no complaints!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by mistercedric: space

Excellent oil

I have used this oil for many years in my 3500 GMC. A recent trip of 11000 km with the 25000 mile oil filter did not change the color of the oil it was still as if it came out of the container. Excellent starting in cold weather

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ivan: space

Excellent Stuff!

Great oil at better than dealership prices.
Why wouldnt you?

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 100 MPH: space

Excellent

I love this oil I rely on it with my lively hood. Great stuff.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Danny Boy: space

Trust

I don't know if my 2013 Ram diesel is protected better by using Amsoil motor oil, but I trust Amsoil research. I believe what Amsoil claims. I can only say this about Amsoil. Only time will tell as the engine ages.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Tamworthsat: space

Great

I would buy this top grade again because I once bought the XL grade and notice a slight drop in mileage.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mark: space

Nothing else for my diesel truck

I have been using Amzoil in my 2008 Dodge Ram 2500 since the first oil change. I currently have 147,000 miles on it and it doesn't burn a drop of oil, runs smooth and has a ton of power. I believe that using a quality oil with regular oil changes is the key. This stuff is not cheap! Neither is this truck! But to replace it is $68,000. I think the Amzoil is going to give me that quarter million mile mark.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by -King D: space

Too much sauce

Perfect

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Benny: space

I have more faith in this product.

I work my diesel trucks hard. Pull heavy loads 100% of the time. When it's 0° and they start up with quicker oil pressure and less engine clatter, or when it's 95° out and I'm wide open throttle for miles up a long steep grade and my oil temps maintain a steady temperature, I feel more confident my engine will last longer with Amsoil.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by 204man: space

Love it

Cold start 2016 cummins. -23. No problem. Amazing in cold temps.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Frank: space

Only the BEST for Me

I have been using Amsoil since 1979 and I believe in putting the Best Oil in all my Toys . I use it in my cars,garden tractor , lawn mower , whole house generator , power washer , and my 2 Corvettes ,and in my 2013 Kioti CK35 HST Diesel tractor . I guess you could call me an Amsoil Junkie 😎

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Arthur: space

Loyal customer

I just changed the oil in my 2015 with Amsoil for the first time, because the truck came with 2 years of maintenance when bought new, and if you didn't use it your just wasting money.i am a firm believer in Diesel injector clean, I'm on my second Duramax and have never had a fuel related problem. I'll use Amsoil forever.
Thanks for great products.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Clay: space

Works good in cold weather.

08 Duramax 250k miles and still going strong. -30 here in winter, starts up with good oil pressure no waiting on the pressure gauge to pick up cold oil.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by JERRY: space

I change my own oil - have for 30 years. Always Amsoil.

When Amsoil produced a oil meeting Chrysler's requirements (2015 Jeep GC 3.0 Diesel) I jumped on it as I have always had good experience with Amsoil oil.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Marc: space

Best oil for my Cummins,

Only product I use. The BEST!

I use it with AMSOIL FF and bypass filters.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Rob: space

Best 15-40 diesel oil on the market

Excellent product, my 2005 Cummins runs smoother than it ever has. I feel very confident pulling some of the heavy loads that I do, knowing that this oil will stand up to whatever I can put it through.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mark: space

I'm going to continue using this product.

Very pleased with the purchase. Regens intervals have increased by a significant margin, particularly in the city driving.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Jeff: space

I will stick with Amsoil.

I've been using this in my 2004 Dodge Cummins diesel for 12 years and 120,000 miles and it still runs like it was new.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Douglas: space

5 Star's will always use amsoil

Best oil on the market ! My 2011 Ford F 250 6.7 deisel has 99.687 miles on it and uses no oil between changes !!!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Dk: space

Winter start

Truck not plugged in -40c slow crank still started. I believe 5-40 made the difference. Good oil

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Novy: space

great

Been using this oil for a while and like it. Cold weather starts a breeze!!!!!!

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by big boy: space

outstanding diesel oil.

could not think of a better oil. longevity, performance, and mileage difference is evident. recommend it for all diesel vehicles. No complaints.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Ihmachine: space

Great product would recommend.

I use amsoil in my 07 diesel truck, I have 7,000 miles on the oil change and still clean according to the lab test! I've used amsoil in different motors and I'm a believer, this oil is spectacular from my personal experience.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by BWW: space

My Ford F250 diesel loves it.

Have been using this product in my 2011 ford diesel since day one. I put on about 14,000 miles a year and change my oil once a year. I have never had to add oil between oil changes. I'm amazed even at change time the oil is still so clear its hard to read the dip stick. Ive been trying to figure out something to put on the dip stick to see the oil easier.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Kevin: space

Easy starting in Canada's North

I have been using AMSOIL Premium 5W-40 Synthetic Diesel Oil for the last five years and I have never had any issues starting when the temperature drops below -30C/-22F.

I switched to AMSOIL after my first winter because I was not happy with the cold weather starting performance of other full-synthetic diesel oils.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Master Bear: space

The Best!!

Amsoil Premium 5W-40 Synthetic Diesel Oil is the best! I have used it on my diesel vehicles for years, and have been quite satisfied with its longevity and performance.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by JP: space

Excellent oil

2011 F250 6.7L. Great oil with great customer service to back it.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

A Verified Buyer is an individual who has purchased the reviewed product and submitted their review through a specific process that tracks purchase history.Reviewed by Mike: space

Will be buying this for years to come

Excellent performance in my 6.7 power stroke

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)

Reviewed by Ronald Glen: space

Much smoother than RT6

Switched over my 6.0 Powerstroke to Amsoil DEO. After some contemplation, I decided to go with Amsoil for few dollars more than Rotella. I am glad with the decision as the engine has become noticeably smoother. This indicates lower internal friction which will translate into longer engine life. I am already getting 50-70 miles more miles per tank of diesel, which justifies for the slight premium in the price.

Also it appears that I can go longer on the oil. I personally don't believe & was not planning on extended drain intervals as suggested by Amsoil. But with the way things are going, I feel comfortable going 50% more on the oil, which again justifies the higher cost of the oil.

I'll continue with Amsoil DEO, its working out to be lot less expensive than RT6.

Item Reviewed: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)
Discussion Url

Re: Much smoother than RT6

To overcome extended drain anxiety, consider doing used oil analysis 1000 miles before scheduled oil change.

You can confidently, continue with the oil if the report indicates all the levels to be within spec. Repeat the oil analysis again until the report recommends changing the oil.

This is the most informed and scientific way to establish oil drain intervals. We see conventional oils breaking down below spec before their scheduled interval, indicating accelerated engine wear (even with frequent and regular oil changes). Therefore, the condition of the oil should be the factor that call for an oil change. Replied by Tech Admin
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