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

As a retired Ford Technician I am very pleasantly surprised by this oil. I have ran Motorcraft and Valvoline for decades. But this oil is amazing actually picked up 2mpg in my 6.0 powerstroke with this oil. Now that I am planning to open my own shop this will be my go to Diesel oil and will run in my personal truck.

Good product from a reputable company

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.

I use it for my 2005 6.0l powerstroke f350. Amazing product, the engine fires right up cold starts hot starts does not matter. My new go to for oil. I bit more money but I dont have to run a Lucas additive anymore.

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.

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

2008 ford 350 6.4

best unknown secret oil out there, oldest oil company in the USA.

I have a 2008 6.4 Powerstroke its some of the best oil that Ive ever used when I started using chafers Ive had the cleanest filters Ive had since Ive owned the truck I highly recommend this to anybody.

Top of the line oil for the Powerstroke.