Just spoke with Ted about changing the oil on a truck with 1000 miles. He said GM Service Shops use a "GM oil". Does anyone know what kind of oil this is? I can buy my own oil and have them use that during the change. AC/Delco filters is what they use. Any last suggestions on what kind of oil to use for a 6.6 with 1000 miles on her?

There are a lot of oils that are good. I use Chevron Delo 400. Refer to your Diesel manual that you should have gotten with the truck to see what standards the oil has to meet. One dealer will probably have a different brand of oil than the next dealer. Also do some searching on the site on oils. You'll get a lot of hits so be ready to do some reading.

I gotta call bs on that one......I know my shop just carries 10/30 for everything and I see a local oil distributor pull up evry once in a while.

Just spoke with Ted about changing the oil on a truck with 1000 miles. He said GM Service Shops use a "GM oil". Does anyone know what kind of oil this is? I can buy my own oil and have them use that during the change. AC/Delco filters is what they use. Any last suggestions on what kind of oil to use for a 6.6 with 1000 miles on her?
GM oil is Mobil which is good, make sure they're using the 15-40 (should be delvac?) and not a 5 or 10-30. I would stay with the AC/Delco filter, they're good filters.

I gotta call bs on that one......I know my shop just carries 10/30 for everything and I see a local oil distributor pull up evry once in a while.


Whats the name of that shop, I want to be sure I don't stop there if I'm ever in the area.Extended use of 10-30 in a diesel could lead to its death.

Just use any oil carrying the ratings listed in the diesel supplement that comes with your owners manual. The recommendations in the manual cover gas engines so make sure you use the information in the supplement. I use Shell Rotella 15-40. Don't ask me why.

GM oil is Mobil which is good, make sure they're using the 15-40 (should be delvac?) and not a 5 or 10-30. I would stay with the AC/Delco filter, they're good filters.

From my past experience, "GM Oil" was just repackaged Valvoline. Do you know of a switch to Mobil recently? I know my dealer does use Mobil Delvac 1300 for the diesels, but that is actually in Mobil containers. The other oil packaged in the GM containers I was told was Valvoline. Both good oils in my opinion.

On the internet is "Bob is the oil guy". Lot's of good resources for oil questions. I changed my oil at 500 miles with Delo 400 15-40w and a Mobil 1 filter. Although Delo 400 is Dino oil and not synthetic, it has a great additive package including moly additives. Mayby at 20,000 I might change to synthetic, but with a diesel it may pay to continue with the Delo 400.

From my past experience, "GM Oil" was just repackaged Valvoline. Do you know of a switch to Mobil recently? I know my dealer does use Mobil Delvac 1300 for the diesels, but that is actually in Mobil containers. The other oil packaged in the GM containers I was told was Valvoline. Both good oils in my opinion.

All I can tell you is that the two local dealers here that have the "goodwrench" oil tell me that it is mobil, this has been for several years now.