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

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

Not very impressed so far. The oil has 3000 miles on it and the 7.3 was filled slightly over the top line on the dipstick before leaving for a 300 mile trip. My truck is ridiculously maintained and has never burned oil in its 240,000 mile life. Pulled into camp, parked and all was good. Next morning it would not fire up! Checked the oil level and was a little below 3/4, added a gallon of delo and it fired up of course after getting oil up to proper levels. In case you dont know, low oil and your injectors wont fire with ford 6.0 and 7.3, awesome system as you wont ever ruin an engine due to low oil. Obviously I do have an issue possibly with a low pressure oil pump but the oil should not burn off like this. No signs, smoke or running problems indicating an issue on the drive. Im disappointed especially after reading all the reviews on the forums over the years and finally getting to try this oil. It ran just slightly better than my regular oil for a few months and then now it runs rough like the oil is old just over 3000 miles. Will not be buying again and am sticking to locally bought oil

Used it for years in my gm crate works great

Noticed mpg improvement. Cant beat moly.

Its the best. Love Schaeffers oil

Really good oil 5/5

Great oil, can go way longer now on oil changes. Saves money on maintance. And motor runs so smooth.

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.

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.

So, I started using this product in my fleet since the Supreme 9000 5W-40 CJ-4 is not recommended for newer EGR/SCR equipped vehicles. Two things Ive noticed: 1. The oil stays cleaner much longer 2. The buses use much less DEF. Because this is made by Schaeffers, I trust that the durability will hold up and keep my equipment running for many miles.