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
Use in diesel engines and, where appropriate, gasoline engines requiring any of the following specifications:
• 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
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.
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.
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.
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.
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 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.
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 |
Product Name: Signature Series Max-Duty Synthetic CK-4 Diesel Oil 5W-40 (DEO)
Current Rating: 4.88out of 5 stars
Votes & Reviews: 200 vote(s) and 204 user reviews.
Reviewed by Joe: 
Eliminates the typewriter noise that most owners of the Lmm Duramax hear. Been using Amsoil products for years in all of my engines from motorcycles to mowers.
Reviewed by bikeman41:
Once a year oil change!
Reviewed by Dirty dave:
Great product , does more than what it says. All fluids in trucks and dirt , street bike .
Reviewed by Hand Cannon:
Amsoil is legendary synthetic oil. I purchased the Amsoil dual bypass oil filter and wanted to compliment the protection for my vehicle by adding the best synthetic oil available. After doing my research, I feel as though I am providing the ultimate protection for my truck. I am no mechanic, however, truck runs excellent and I am pleased with my purchase. Extended mileage oil change is a big plus.
Reviewed by Drivr51:
I use this product in my 2014 Silverado 2500 duramax diesel. The intervals between oil changes are phenomenal. All amsoil product lines are worth the money including this max duty diesel oil.
Reviewed by JG:
Great oil! All of my UTVs, farm equipment, and trucks are diesel. When in the northern sections of the country and extremely cold, there is a noticeable ease with startup vs conventional oils. I'll never go back.
Reviewed by Audie Baca:
Great product! Been using the diesel oil since my truck was new. Truck now has 155,000 miles and hasn't skipped a beat!
Reviewed by Rocketman:
I have all confindence in Amsoil products and will use them always.
Reviewed by Sixpack:
Covers my 6.7 in cold conditions
Reviewed by Pj:
This is an outstanding product
Reviewed by Seabass:
I swear by amsoil for anything i own and always will
Reviewed by Mark:
I use this product in a 2012 Ram with a 6.7 Cummins motor. The oil does get very dark between changes.
Have not had any issues, and motor oils do get strained with diesels.
Reviewed by Chumleyy:
Truck really loves this oil, since I've made the switch!!
Reviewed by Rusty:
Never had a engine go down using Amsoil. Put a ton of miles on my diesel engines as well as hour's. All is good.
Reviewed by Cecil:
This is the only oil I will ever use.
Reviewed by Brad:
I have a 2007 GMC Diesel with the LMM engine and over 300,000km's. I did the first oil change and i was surprised that the particulate sensor said it was due for another change within 5000km's. I figured it was cleaning out the carbon and residue from the old oil change and changed it again. This time it went longer but still less than it should. The third change we went on a family vacation which involved towing our trailer over 6000km's. Came back and still had over 30% left. I suspect inwas right and this oil was cleaning out the deposits and gunk from my old oil. Moral of the story, if it seems to be getting dirty faster it probably is, but once it is cleans out the old seems to last longer and work better. I'll let you know in another 100,000km's or so.
Reviewed by Andy:
I use this oil in my ecodiesel, I just recently did an oil analysis and it came back perfect. I will continue to use this great product
Reviewed by Mike:
Truck runs quieter. Especially in cold weather.
Reviewed by Dave:
I change my oil once a year his oil allows me up to 25,000 miles before I have to change.
Reviewed by Tak:
I run Ams oil in my truck, SUV and motor cycle .It costs a little more but to me it's worth the extra cost.. I tend to push my oil changes a little longer so I just use what I think is the best.
Reviewed by Dieseldog:
I will always use Amsoil in any vehicle that's worth anything to me!
Currently driving a Cummins and the difference is extremely noticeable!!!
Power increase, less noise, just about eliminated my oil loss and seems to have even improved my fuel economy. It's like liquid gold for my engine!
Reviewed by Bobby:
I purchased the signature series diesel oil and filter and after 6,000 miles, I decided to send my sample to a third party for testing. The report came back stating my oil and engine health was one of the best they've seen for an engine with over 200,000 miles.
Reviewed by Will:
I use this product in my pick up that has a Duramax and it with 187,000 miles
Reviewed by Brian:
Amsoil is a very good oil for my echo diesel dodge truck. I have used Ams for years and I am sold on the product.
Reviewed by Yelly:
We have used amsoil on our farm and if it holds up there it can hold up to any thing! I won't use any thing but amsoil products in every thing I own!
Reviewed by red:
great product
Reviewed by Dan:
I have nine diesels on the ranch and use Max-Duty in all of them including a few gasoline engines. Works like I expect it to work.
Reviewed by Rick:
Use this in my 12v Cummins was adding about a half a quart of oil every 1000 miles before switching to to this oil now it's about a half a quart every 4000 miles and I change it every 5k.
Reviewed by Dirtman:
if you want the best protection for your engine buy amsoil. I use it in everything so my equipment will last.
Reviewed by Friedrich:
Hands down the best oil out there i have tested my oil after it comes out and still have amazing tbn numbers in ty he 5 range with 7000 miles on that oil
Reviewed by Andy:
Switched my 2015 powerstroke over to this when it hit 20k miles. Now at 135k and zero problems. When it says "change oil soon" I go online and order it, 2-3 days later it is here. Wish there was a better price break on the gallon jugs rather than having to pour in 13 individual quarts as it is cheaper by the case.
Reviewed by John:
When I ordered my duramax in 08 I wanted to run the best oil and fluids because I don't plan on buying another 65,000 truck. I researched extensively and found the decision easy. Everything but the radiator has amsol. I'm at 320,000 problem free miles. With the exception of the headlights that regularly burn out, I haven't had one single issue with my truck. I bought a 24' triton boat with a 300 yamaha and the day my warranty ran out it also got refilled with amsol marine oil. .
Reviewed by navret02:
Was introduced to this oil and it really works. Protecting my 6.0 Diesel Engine under any load, especially with the Bypass oil system!
Reviewed by Bob:
The total Base number is way too low for my liking since they changed the formulation. I am switching brands of oil.
Reviewed by Gene:
I like the way it keeps my engine clean and running free.
Reviewed by charlie:
well this is the best oil ive ever used on my diesels lol I tried out the amsoil in a way that most peoples wont ever or even try to see how long it actually lasts before it completely breaks down ,, soo what I did was I just kept changing the oil filter every 12 thousand miles until it finally broke completey down lol I made 43,768 miles and that where it actually just burned out but all and all its the best in the world !!!!
Reviewed by Carlos:
I have been using Amsoil since 2009.
Reviewed by Pete:
I have tried every kind of synthetic for a diesel engine and found AMSOIL to be the best by far. I have a E350 Ford van with a 7.3 power stroke engine. I have gained two miles per gallon and the motor runs smooth.
Reviewed by Kevin:
First 10K was great, pushing this last oil change to 25K will update review after my oil analysis is done.
Reviewed by Don M:
Primary use is for my Cummins 6.7 in my 2014 Dodge Ram. We use the truck for towing and I feel that Amsoil Signature series helps protect my truck in severe duty towing.
Reviewed by Austin the concrete pumper:
Well, the reality is... Diesel maintenance is expensive, no two ways about it.
With this oil I can run longer intervals with less deterioration and degradation, even on the heui engines I own and maintain (which works oil to the max)
I have to say, with the oil analysis that I get back consistently telling me that my engines are happy to run extended change intervals ((while still changing filters at normal intervals)) I'm a happy camper, over the next ten years I'll save tons of money.. tell me that wouldnt make you happy.
Reviewed by Casey:
I use this product in my Ford F250 6.0L PSD. I noticed my turbo spooling up easier and quicker after switching from conventional oil. The 6.0L PSD's are very tough on the oil due to the high shearing of the oil pressure run fuel system and the lubrication of a hot turbo. Many professionals highly recommend changing at 6000 miles in the 6.0 PSD. I run my diesel kind of hard with pulling a lot of heavy loads and running a hot tune for daily driving and playing around, my last oil change was at 9000 miles. Oil was still full without adding any, still feels more slippery than new conventional. I reuse it in old oil burning engines and it cuts the oil consumption in half. A relative of mine has been using my drained Amsoil in their beater car for over a year and it cut way down on the oil consumption. I would run the oil longer in my 6.0, but like to recycle it into the older engines. I use only the Amsoil long life oil filter. I may purchase the oil test kit in the future just to see if there is any depletion in the strength of the oil, but I am very happy with my use of this product.
Reviewed by Ryan:
So glad I've switched to Amsoil products! I want nothing but the best going in to my engines. Outlasts any lubricant I've ever used in my vehicles.
Reviewed by AA RON:
Amsoil synthetic keeps my work truck running and me making money. The only way to go.
Reviewed by MR G:
My cummins runs so much smoother
Reviewed by None:
Best oil made
Reviewed by Robin:
I trust this product compact to what we getting out there it is proven to have the correct antiwear detergents blend into the oil and you can listen to the effectiveness and quieter motor when idle and driving at your cruse speed
Reviewed by SD:
I use this on my 2018, Super Duty 250
Reviewed by Hawk:
The best oil product I've ever used.
Reviewed by STW:
GOOD STUFF
Reviewed by Matt the Hunter:
I use this in my Daily Diesel Truck,I love the power it frees up.
Reviewed by Bigb:
200k on my cummins diesel with amsoil.still like new.great stuff.
Reviewed by Jr:
Use this oil on 17 duramax works great glad i can get quality oil shipped to my door gives me peace of mind my truck has the protection it needs to do its job
Reviewed by Ink:
Upon purchase of a new Toyota the service rep recommended Amsoil. I use Amsoil in a 2014 Tundra, a John Deere 748 Diesel, a 2017 Camry, a 2014 Outback, a 2016 Highlander, and a Honda lawnmower. Well satisfied at this time.
Reviewed by J-Rod:
This diesel oil is the best stuff out there! I use everything AMSOIL!
Reviewed by MB:
Amsoil products fit the bill for almost any application @ a affordable price.
There products are vastly superior to most on shelf products, They even make
specific products for specific needs. all this with great tech support and easy online
purchasing. I will continue using Amsoil products for these reasons.
Thank you Amsoil.
Reviewed by Eddie:
Great stuff. I've been running this stuff for years. About 15,000 miles per change. I know several people that have ran it the full 25,000 miles.
Reviewed by Perez:
I have an 05 6.6 duramax and like that this oil gives me more miles between oil changes.
Reviewed by Gus:
So far so good, like to put 15w 40 synthetic on my Cummins. Lets see next oil analisis how's holding up.
Reviewed by Mike:
I've been using Amsoil in my 04 Ram 5.9 L Cummins almost since it was new. 280,000 miles and no engine problems at all!
Love it!
Reviewed by Jarvis:
Solid premium product. I try to take care of my vehicles the same way I do my body. I look for the full protection of the lubrication this product provides in the rigorous operations I put my truck through, and the many miles I do. I'm happy with it.
Reviewed by Steve the boss:
Have used the diesel oil in my Ram from Day one. I believe it's the best on the market. I trust it.
Reviewed by Chad:
Changed all the fluids in my 99 Superduty(220000 miles) over to Amsoil products. Truck starts easier in cold weather trans temps have dropped 10-15 degrees towing and I gained 2 MPG.
Reviewed by Wild Bill:
Used in my 2014 Ram 1500 Eco Diesel
Reviewed by Pdnh:
Was using Mobil Delvac 1. Would change oil at 15000 miles, changing the filter at 7500. Doing oil analysis at 15000 miles the oil was at 70%. Switching to Amsoil I change at 25000 changing the filter at 12500 the oil is just a little over 80%. Results speak for themselves.
Reviewed by Justo:
I am using the amsoil for the last five years
About 100,000 and 120,000 miles per years
My semi truck and me we are happy and saving money it's amazing for the best
Reviewed by Jemeda11:
In my diesel trucks. Awesome oil. Lasts 25000km before I even think of changing it.
Reviewed by Vegadriver:
Run this oil in my 2012 Duramax. Can go a full year without oil change. Saves me money. Also use the Amsoil filter.
Reviewed by JasonV:
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.
Reviewed by NYMustang50:
Stuff is worth every penny. Oil analysis test prove it. Always use Amsoil in all my personal engines.
Reviewed by PAPPY:
ALSO IN MY SS2 CAMARO
Reviewed by DWS:
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
Reviewed by Ron:
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.
Reviewed by BRIANS cummins:
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
Reviewed by Mark:
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
Reviewed by Reg Moody:
Used in all my vehicles for years
Reviewed by Mike:
Maintenance
Reviewed by Dogman:
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!
Reviewed by rdj519:
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
Reviewed by Jack:
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.
Reviewed by obg:
Great stuff wouldn't use anything else.
Reviewed by REJ:
This is the only product that I can find that is recommended for my Eco Diesel and it performs as advertised.
Reviewed by Mike, 2017 Dodge Ecodiesel:
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.
Reviewed by Pinkpeaches10:
Perfect oil.
Reviewed by Doc Pat:
I use this on my 3 diesel trucks. 1985, 1994 and 2001 F 350.
Reviewed by JGD:
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.
Reviewed by Jonathan:
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
Reviewed by Russell:
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.
Reviewed by Butch:
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.
Reviewed by Joe:
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!
Reviewed by Scott:
I believe in synthetics and Amsoil.
Reviewed by Doug:
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
Reviewed by Jason:
I use this product in a 3/4 ton work truck.
Very high quality product.
Reviewed by Grandpy:
No worries
Reviewed by Super04FX4:
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!
Reviewed by Ray:
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.
Reviewed by GregM784:
Runs great, runs cooler, a product you can trust.
Reviewed by Tom:
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?!!
Reviewed by Mud Creek Ranch:
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.
Reviewed by G513:
Really haven't noticed any real benefit over cheaper options. The cost is a major problem.
Reviewed by James:
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
Reviewed by Matt Z.:
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!
Reviewed by Gregory:
I switched to this oil from 5w/30 Series 3000
Because of price.
Reviewed by 7Trumpets 42:
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!
Reviewed by Hauss:
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?
Reviewed by Rock:
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.
Reviewed by RAV:
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.
Reviewed by Bam Bam:
I drive 114 miles a day for work
Reviewed by Bentley:
Feels like my trtuck runs a lot smoother
Reviewed by Pete:
Love using the best protection available for my Chevy 6.6 that I work hard everyday and with 123,000 not a single hiccup.
Reviewed by Chuck:
I would and do buy it all the time
Reviewed by Chuck:
😉
Reviewed by Dave:
Engine ran cooler in summer by five degrees with Amsoil. -25C starts not an issue, even when I forgot to plug in.
Reviewed by Sky Pilot:
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.
Reviewed by Stan H.:
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 .
Reviewed by Greg:
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!
Reviewed by Josh:
This is a high mileage truck 350,000 km it starts great in cold weather and a faster clean start
Reviewed by Phil:
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.
Reviewed by Airstreamer Joe:
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.
Reviewed by Mike:
When I start my engine at -35 degres celcius it runs smoothly.
Reviewed by Mike:
When I start my engine at -35 degres celcius it runs smoothly.
Reviewed by Mike:
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!!!!!
Reviewed by Jamie:
This oil flows pretty good when the temperature gets down to zero.
Reviewed by Wild Bill:
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.
Reviewed by Doubleplay7:
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.
Reviewed by Amsoil Believer:
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.
Reviewed by Z:
Use in my tuned 2006 2500 Dodge Ram Laramie Mega Cab. Many miles and still runs like champ!
Reviewed by Eric:
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.
Reviewed by Al:
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.
Reviewed by Slick Nick:
I'm using it for year in my semi and never left me down. Great quality lubricants.
Reviewed by Ode:
I use this in my ram 1500 ecodiesel. It performs well. No usage with 49k miles.
Reviewed by Moparguy:
Awesome product. Long time amsoil user. The products just get better!
Reviewed by Greg:
The ONLY I will put in my '16 Ram 3500 Dorsal!
Reviewed by $ilver6_7_cummins:
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!
Reviewed by Kissoondath Rovin:
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
Reviewed by Steve:
Excellent at every point.
Reviewed by The real noble:
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
Reviewed by Ray:
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.
Reviewed by Ron:
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.
Reviewed by Fordfan:
excellent
Reviewed by Cooory Ed:
Great oil
I run amsoil in everything
Reviewed by Muleboy:
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.
Reviewed by Kyle:
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.
Reviewed by Pat:
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.
Reviewed by Jon Driver:
Under heavy usage and need peace of mind
Reviewed by Chris:
My engine is still running and since I can't see inside it, it must be working.
Reviewed by SG:
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!
Reviewed by Rick Wysynski:
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 !!!
Reviewed by Phil in Tulsa:
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.
Reviewed by Kelley:
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
Reviewed by patrick:
In my Excursion Diesel 250,000 miles
Reviewed by F450:
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.
Reviewed by Dave:
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!
Reviewed by Nimble:
Use it a 09 Chevy Duramax, starts great even if it hits 0 or below
Reviewed by John R:
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.
Reviewed by Matt:
Engine ,primary and transmission fluid for my fxstdi.
Reviewed by jobu:
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
Reviewed by Ryan:
My son uses Amsoil in his 2011 Ford F350. He has many mods on his truck. This is the only oil that he trust.
Reviewed by Rob:
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.
Reviewed by Big Frank:
New 2017 ford diesel. Outstanding oil. Highly recommend it. Would only use this oil in my new Diesel engine It is so high tech
Reviewed by None:
Ran for 8 thousand miles & love it so far
Reviewed by Dimonic:
I like to do my own oil changes, and avoid all the "additional" services the dealer offers.
Reviewed by Cumminswitit:
My truck and I love this stuff. I run it for a year between changes and love it. Best oil out there
Reviewed by elkoholic:
Truck is used for hauling horses.
Reviewed by Petro:
I use Ams oil in every application of my truck and never have I been let down
Reviewed by MURF:
IN A DODGE SPRINTER
Reviewed by 4B RANCH:
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.
Reviewed by Randy:
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 ..
Reviewed by engr:
looks good. I will need more time to fully evaluate it.
Reviewed by truckguy12:
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.
Reviewed by Trev:
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...
Reviewed by J:
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.
Reviewed by Steve:
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
Reviewed by DWC521:
My 2016 F350 6.7L runs smoother on this oil
Reviewed by Hurst:
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!
Reviewed by mistercedric:
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
Reviewed by Ivan:
Great oil at better than dealership prices.
Why wouldnt you?
Reviewed by 100 MPH:
I love this oil I rely on it with my lively hood. Great stuff.
Reviewed by Danny Boy:
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.
Reviewed by Tamworthsat:
I would buy this top grade again because I once bought the XL grade and notice a slight drop in mileage.
Reviewed by Mark:
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.
Reviewed by -King D:
Perfect
Reviewed by Benny:
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.
Reviewed by 204man:
Cold start 2016 cummins. -23. No problem. Amazing in cold temps.
Reviewed by Frank:
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 😎
Reviewed by Arthur:
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.
Reviewed by Clay:
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.
Reviewed by JERRY:
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.
Reviewed by Marc:
Only product I use. The BEST!
I use it with AMSOIL FF and bypass filters.
Reviewed by Rob:
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.
Reviewed by Mark:
Very pleased with the purchase. Regens intervals have increased by a significant margin, particularly in the city driving.
Reviewed by Jeff:
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.
Reviewed by Douglas:
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 !!!
Reviewed by Dk:
Truck not plugged in -40c slow crank still started. I believe 5-40 made the difference. Good oil
Reviewed by Novy:
Been using this oil for a while and like it. Cold weather starts a breeze!!!!!!
Reviewed by big boy:
could not think of a better oil. longevity, performance, and mileage difference is evident. recommend it for all diesel vehicles. No complaints.
Reviewed by Ihmachine:
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.
Reviewed by BWW:
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.
Reviewed by Kevin:
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.
Reviewed by Master Bear:
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.
Reviewed by JP:
2011 F250 6.7L. Great oil with great customer service to back it.
Reviewed by Mike:
Excellent performance in my 6.7 power stroke
Reviewed by Ronald Glen:
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.
Re: Much smoother than RT6
To overcome extended drain anxiety, consider doing used oil analysis 1000 miles before scheduled oil change.
Replied by Tech Admin
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.
Works great in my F350
I use AMSOIL in all my vehicles and they operate great.