Lmm Duramax Engine Oil

TheGuyX · December 17, 2007

I have a new 2008 GMC Sierra SLT with LMM Duramax Engine. I now have about 2300 K on it. I am leaving next week for a Northern Trip to a fairly remote area. I will put on about 5000 k on my trip. I stopped by my GM dealer where I got the truck and asked for a Litre of Oil, just in case I ever noticed my oil down during this trip. I expected that I would be changing the oil some time after I was back. The dealer gave me a litre of Quaker State 15W-40 Universal HDX ( for heavy duty diesel engines ). It has SAE of CI-4, CH-4, CF/SL. When I got home I checked my owners manual and it says that oil must be CJ-4 or better. So back to the dealer I go and they tell me that this is the oil they use for all the oil changes of diesels. I mention that my owners manual says CJ-4 and after some discussion the dealer finds a bulletin advising of the new oil and they have to order it in and it will be a couple of weeks because they get it from GM. It is a Mobile Synthetic Oil. I tell him that I wanted a litre to take with me and of course they will not have it in time and it only comes in 4 litre containers. The Service Man then tells me that the Quaker State is fine, that it just has a slightly differenct ash content and will be fine for my LMM. He also states that the Oil in my LMM from the factory is a Synthetic Oil.

I checked on the Web Site for Mobil 1 oils and found there is a Mobil Delvac 1300 Super that meets the CJ-4 Spec. and there is also a Mobil Delvac 1 ESP Synthetic Oil that meets the CJ-4 Spec. I went to Canadian Tire and they do not have the new Oils yet. So I have a couple of questions.

1. What kind of oil is in my LMM Duramax from the factory. Is it Synthetic or not?

2. If it shows low on the dipstick before oil change is due, what should I put in it and where would I get it ??

3. Is it true that CJ-4 only has lower ash content and I could use the CI-4 also.

4. Where can I get CJ-4 Oil right now and should I Switch to the Mobil Delvan 1 ESP Synthetic when I do my first oil change. ( If I can find it. )

Lots of questions and will appreciate any answers that you have for me.

Thanks

Jacques Brassard

dlstewart01 · December 18, 2007

You need to ask this question on www.bobistheoilguy.com

Have a good one,

Don

RCH · December 19, 2007

I found Mobile Synthetic for diesels with the CJ-4 rating as well as Shell Rotella and Chevron Delo at Wallmart. I don't think the Rotella is a synthetic. Just be sure to remove the cap and check that the seal has not been broken. I've heard of people buying synthetic only to get it home and find out that the synthetic has been switched out for petroleum based oil by someone wanting to save a few dollars. K&N oil filter for that is # 3003. The CJ-4 rating is lower ash. I am using Amsoil synthetic right now, but at my next change I'm going to the Mobile synthetic. Have a good trip.