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

I like that oil very much,(addicted to it) tried this oil in different cars, works perfect Ram 3500 Cummins 6.7, towing Goosneck, got 20000 miles of oil change. Mersedes ML350 Bluetec 15000 of oil changes, analyzing oil after 30 to 52 % life left.

Good oil.Had it before, but dropped after ingine start eating oil.Since bouthg different semi start using again.

After 2 hours run time its still clean.

Typically the oil in my diesel turns black shortly after a oil change. (this is normal) The Schrieffer oil is not doing that as quickly. Very happy with the oil. I will review it again at 4000 miles during the my next oil change.

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.

Excellent oil!! Runs well on the 2003 6.0 powerstroke.

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

Really good oil 5/5

This stuff is the best on the market for a 6.0 Diesel. I’m crazy I have sat for hours reading forums about the most asked about ,debated and discussed topic……best oil for my 6.0 diesel. I’ve literally tried Shell non synthetic and full synthetic Ford OEM oil and a few others. This with with Archoil AR91000 along with some form of ZDDP additive is hands down the best lubricant package you could ever put in this F-250 6.0 diesel period. STOP SEARCHING AND WASTING YOUR TIME IVE DONE THAT FOR YOU ALREADY!! Just pull the trigger!! PS Use OEM oil filter ONLY and change fuel filters every other oil change!!!

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