Schaeffer Manufacturing Co. 0700CK4-012 SynShield Durability Advantage 15W-40 Diesel Engine Oil, 12-Quart Bottle (Pack of 12)

Excellent oil, I used this in my 2015 f250 diesel, and the engine oil runs 8 degrees cooler than it did before. First time I actually seen a difference in an oil like this, really lived up to its name ,will buy it again.

I have been driving diesels for 30 plus years and 1.5 million miles. I believe that this oil and all Schaffers products are the best Ive used. Since using this oil Ive had two b series Cummins go over 700,000 miles without touching the engine other than to adjust the valves. I use Schaffers in the tranny and differentials as well with same no failures results. I always rebuild my auto trannys at 300,000, clutches wear out no matter what, and shop said the externals look almost new each time.

2008 ford 350 6.4

Theirs no better oil on the market

Would give this 10 stars if I could. Oil makes my Cummins a lot more quiter. Doesnt shiver like a chiwawa anymore and oil change intervals now at 7k miles.

Fantastic oil but one of the quarts leaked a couple ounces during transit.

One thing to point out this OTR 10W-30 is (0711CK4-006S) - which is a Semi-Synthetic... The (9012) OTR 10W-30 - (09012CK4-006S) is the 100% Full Synthetic - similar to the formulation of their 9000 5W-40 Full synthetic... I did not realize this until now - I spent 30min looking over Schaeffers website & finally found 2 types of OTR 10W-30... Just wanted to point this out - so buyers who prefer a 100% Full Synthetic was not mislead...

Read a lot of great things about this oil for use in my 6.0 PSD, just towed my travel trailer to Charleston SC and ran very well,oil temps alw a ys good even though we were in 95 ambient temps running 60-65 mph.

Excellent oil!! Runs well on the 2003 6.0 powerstroke.

Great fuel economy, incredible oil!