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

Best oil on the market. Its costly but worth it to keep your motor lubed and clean. This has revived my old 01’ Dodge Ram 2500 Cummins.

Swapped to schaeffers from Rotella 15w40 and noticed increased oil pressure, slightly better fuel economy, and a quite engine. I was quite impressed. Its really good oil, but... the downside is the price, I recommend going through a nearby sales rep as the prices are exponentially cheaper than buying from a 3rd party vendor such as Amazon, Napa, O Reillys etc.

This stuff is in fact.. the cats MEOW!! I would only recommend this formula for cooler climates before running it myself, but it in fact holds its own in severe heat as well! It holds slightly more oil pressure than Rotella 10W-40 at the same temperature! I’m pleased! I’m running this in everything I own now!

Great product as always from Schaeffers

We use this oil exclusively with our Diesel Trucks because its good quality but for some reason I cant get Amazon to deliver it anymore. They keep giving me the excuse its undeliverable each time. So I guess I will have to get my product elsewhere.

Great oil, from a trusted, and well respected manufacturer. Buy this CK-4 rated oil with confidence.

The best oil money can buy. I use it in my 1999 dodge cummins diesel

Best oil for Ford 6.7 Powerstroke, hands down.

This is a good oil, but it is very expensive for the value. Lucas Oil 10299 SAE 15W-40 CJ-4 Synthetic Motor Oil works just as good for half the cost. Schaeffer oil is good but not worth the extra cost.

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.