Been using in my '07 Duramax for the last 10 years. I change the oil and filter every 5k miles. I use my pickup for towing fairly heavy loads on a gooseneck flatbed trailer and the engine seems to be doing what I ask. I used to use Chevron Delo 400 but at the time I switched, my neighbor was a long-haul driver making trips from WA to PA and said the Delvac was all they ever use in their semi truck.

Best oil I've ever used in any tractor! Literally cleans the engine and you can go more miles in between changing oil than with other brands. All my tractors are diesel, would highly recommend!

So many motorcyclists use Shell Diesel oil, Mobil makes excellent products so I put this in my VStar for less $.. So far so good.

High quality engine oil for a fair price

Good product excellent service

I own a mobile diesel repair shop and this is buy far the best oil for the money i cant touch oil of this quality for cheaper then this

I have used Delvac exclusively in my DD15 for its entire life. 888,000 miles and counting. With NO rebuild! Changed at 25k give or take with 1 gallon of Lucas also included. Never had a bad oil sample report.

For my diesel truck I like this oil because it has the Zinc required for the engine.

Great price on sale. Works as good as any other product.

Good oil, Used it for years.