Royal Purple 04154 / 300905 Duralec Super 15W40 CK-4 Motor Oil Synthetic - 1 gal. (Case of 3)

Been using Royal Purple in my Cummins diesel engine for 10 years and the valve body looks new. Very good oil although it's a bit pricey. You get what you pay for.

Would buy again

Everyone knows royal purple’s reputation for great products. I have used their oil in my diesel engine for ultimate engine wear protection. Pricey but so is another engine. This will help your engine last longer with fewer oil changes.

Good price fast delivery

I run this in my 2011 Duramax I was previously going through about 2 qts every 2,000 miles (depending gow hard I was working it) switched to royal purple and now I use NONE this Duramax has had extensive engine work bigger injectors bigger turbo different crank and connecting rods new injection pump and air dog lift pump it is deleted Fithian a 5 stage tuner and turns right at 560hp at the wheel as a daily driver and after royal purple I am also now getting low 20's for fuel mileage of interstate and get "25 ish" on regular highways at 55mph I have now started running royal purple in my tractors as well love the product!

A few reviews rate this oil as not all it could be for the money. Yes, it is a bit pricey. But for my 2011 Itasca Meridian coach equipped with a Cummins ISC 380HP diesel, nothing compares. I have my oil tested annually and the reports are good. I am able to get about 10K miles between oil changes. I use this brand in my generator and car. Have tried others but I could tell that performance always suffered. This is a very sticky oil and does thicken slightly towards the end of its useful life.

Good price for what I need.

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