Mobil makes a 5w-40 Synthetic and states on the Mobil website that it is approved for the duramax engine. Will the 5w-40 make a huge difference then the 15w-40 mineral oil that is recommended? Can I use this safely?


Petro-Canada makes a syntheic blend 15w-40 Do you think that this might be a better choice?

Mobil Delvac 1? If so, use it. IMO it's the best oil money can buy.

It should be fine to run that through the summer since your probly gonna need a 5w-40 in the winter anyways up there in canada

I run Mobil Delvac 1 5w40 year round for what its worth. Where in Canada are you?

I'm in Northern Alberta Max but I just spent a week in Manitoba on vacation.

There's lots of information and opinions about oil on the site, plenty of reading to keep you busy.


Just make sure what ever oil you select meets the API service standard for your truck...http://www.dieselplace.com/forum/smileys/Geek.gif


Welcome to the forum...http://www.dieselplace.com/forum/smileys/Hug.gif

Just changed my oil last Friday. Replaced the Delvac 1 with Mobil 1 Truck & SUV (supposed to be the same as Delvac 1). Picked up 10 quarts of the stuff at Wally World for $4.77/quart. I wish they would carry it in the 5 quart containers that they have all of the other Mobil oils in.

What was the oil viscosity on the mobile 1 15w40 or 15w50?


I have seen the 15w50 mobil 1 oil at wallyword in the 5 qt jugs.

... I have seen the 15w50 mobil 1 oil at wallyword in the 5 qt jugs.


M1 15W50 does not meet the CI-4 spec. The Dmax requires a CH-4 or CI-4 rated diesel oil.


http://www.dieselplace.com/forum/smileys/Geek.gif

The Mobil 1 Truck and SUV is 5w-40.