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

AS A TECH I HAVE SEEN WHAT THIS OIL CAN DO TO A ENGINE AND I WILL NOT USE THIS OIL IN ANYTHING !

All good

This oil company is the best in the biz!

I can’t say enough about this Diesel engine oil. Best stuff on the market.

I use this oil in a 2007 F-350 SRW 6.0 bulletproofed powerstroke and also a 2020 Ford F-450 6.7. It meets the Ford spec and its one of the best oils in a Ford diesel. I have analysis and used delvac, rotella, delo and Amsoil. Best mpg, best wear protection. In 8k miles in a 6.0, total of 9ppm for iron and 3 for copper.

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

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.

Love this oil Only oil I will run in my truck from now on Starts up better and runs quieter

Best oil on the market it’s the only oil I’ve used in my medium and heavy duty trucks.

I’ve put 110k miles on my truck over the last three yrs and finally switched to Schaefer’s. She’s instantly running more smoothly than I remember before the wear and tear. Impressive stuff. Should’ve started using it BEFORE all those miles but this has definitely made a notable improvement.