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

Noticed mpg improvement. Cant beat moly.

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

I like its performance is very good oil

Case leaking oil when it arrived

Its the best. Love Schaeffers oil

Great oil I run it in my 2012 Silverado duramax. I had a whine noise from the oil pump and now the noise is gone, Ill keep using this product

I bought this oil for my 2019 GMC Sierra Duramax diesel, however my owners manual clearly states API CJ-4, ONLY!!! However, further on in my owners manual it includes CK-4??? It would stand to reason that API CK-4 rated oil would be superior to API CJ-4 as this rated oil is older and does not include the latest additives. GM needs to do a better job proofreading their manuals before issuing them with new trucks.

Really good oil 5/5

Only Received 11 qts was in a bag inside a box , no case

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