Schaeffer Manufacturing Co. 0700CK4-006S SynShield Durability Advantage 15W-40 Diesel Engine Oil, 1-Gallon Bottle

She oil does a great job with oil quality and fair pricing for a high performance oriented oil. This oil helps out significantly on my street car that has a junkyard engine in it since running this oil my engine has stayed nice and quiet, and even while changing the oil at shorter increments for this particular vehicle, it is still quite affordable.

I stand by the product with several cars! Once you have the car, change the oil & replace with this product - first oil change! Your engine will hum, run very smooth & crank smoothly (even in the harshest weather) Excellent value for the price and you can run an extra 1k miles before changing oil with this product.

I use this on my backhoe and tractor, after about 2-3 hours of run time on my backhoe after the first time using, immediately improved the overall sound and feel of the motor. Also took the top end off for another issue after a couple of changes, clean as could be, all the internals looked top notch. It does cost more than other brands but I will say I’m pretty confident this is tailored for heavy equipment.

Absolutely hands down the best quality oil money can buy. 7.3 idi at 380k miles & 6.4 powerstroke @ 255k miles. Rocker arms were worn. Not from poor oil, from a faulty design. They probably would have failed completely had I used rosella.

Best diesel oil I’ve ever found. 6.0L powerstroke still running strong at 270k.

Best tastin oil out there

I bought this for my old diesel tractor that makes a lot of engine noise. This oil made it run way quieter instantly. Only buying this from now on.

A fellow diesel/heavy equipment tech told me about this oil 5 years ago and I wish I'd listened then. Just now switched from T6 Rotella to this and my 15 year old Cummins immediately sounds as smooth as it did back when it was new. Well worth the extra cost.