Product Reviewed: OE Series API CJ-4 Synthetic 15W-40 Diesel Oil (OED)
Current Rating: 5 out of 5 stars
Votes & Reviews: 17 vote(s) and 18 user reviews.
Reviewed by SUPERDAVE: 
Keeps my personal vehicles and drag bikes running clean and efficient!!!
Reviewed by ectjr:
I wouldn't use anything else in my diesel pusher motorhome. I travel extensively site seeing and enjoy fewer oil changes due to the quality of this oil.
Reviewed by John Wick:
I like
Reviewed by Matt:
Use Amsoil in my diesel pickup and blown away at its ability to stay clean for more than 6000 miles. As a retired mechanic I'm familiar with oils and engine maintenance. I've never seen such great performance from any oil. I've been sold on Amsoil for a few years now. Recommend to anyone, all the time. Keep up the great work!
Matt
Reviewed by None:
I have used AMSOIL 15W-40 OE oil for well over 20 years, both in my Chevy HD2500 Duramax and my earlier Dodge RAM 2500 Cummings diesel. It has performed superbly. I recently changed injectors at 200k miles and had my fuel rails adjusted. The mechanic said he couldn't believe how clean the engine internals were and how little wear was exhibited. I think I made a convert that day.
Reviewed by Racer 114:
I use Amsoil in all my vehicles. Im not easy on my vehicles. I tow, I race, I work hard all the time and expect my vehicles to perform at all times.
Reviewed by James:
The best oil on the Earth
Reviewed by Clifford:
Very difficult to find full synthetic 15W-40 for my Chevy Duramax. I find I can get the oil delivered to the house, at a better price, for better oil than I can get locally. Kind of a No-Brainer.
Reviewed by DAVE:
Use it on my tired '94 chev 3/4 ton with a 350tbi...keeps the engine clean after running it after a few oil changes..great alternative for something that uses a little oil
Reviewed by Ronald:
Excellent oil, I like and use it.
Reviewed by Pablo:
I love to use the amsoil product BUT the only thing the shipping fee is too high
Reviewed by Air Force Steve:
I have used this oil since my truck turned 10,000 miles in 2003--regular oil up to that point. (Back then the recommendation was to wait until the engine breaks in). I am only putting a little over 12,000 miles a year on the truck and change the oil & filter once a year. The truck turns 14 years old next month and is still running great!. I would like to think part of this truck's longevity is due to the AMSOIL in the motor.
Reviewed by K:
Great Product
Reviewed by Stan:
Well, in my experience with the OE 15W-40 diesel oil can't be beat. The very first time I used it about 5 yrs. Ago I had just taken a 900 mile trip got 20.1 miles to the gallon. Switched to Amsoil 15w-40 and did the very same trip got one mile to the gallon better fuel economy. My engine will even start in extreme cold using this oil and never be at a loss for pressure.
Reviewed by Silver dream:
Tried in my truck to improve fuel mileage and run cooler which it did both
Reviewed by N/A:
I have used this product for one season and will be using it again for the next season. Mercruiser recommends 25 - 40 oil - the synthetic oil that I am currently using from your line of products is 10 - 40. I realize that you are now marketing a synthetic blend 15 - 40 for marine engines. Given that I prefer the full synthetic oil, when will AMSOIL begin marketing a 25 - 4- full synthetic marine oil
Reviewed by Ed the beach:
I yes all your products in my landscaping equipment and my 2008 dodge ram 3500 with a Cummins
Canada
United States
I use this in all my vehicles
Ram 2500 diesel runs smooth and cleaner