2013 Yukon XL Denali - introduction and questions

[donjetman]

It looks as though you went to a diesel oil? (5w-40) I wonder if the different additives did more of a cleaning process.

I like how serious you are on oil changes BTW. Thanks for rhe insight. I go by miles, then oil color on the stick, them color when dropped. After that it's all new and no cares. Some ATF every few changes to wash stuff out in the last 500 to 1k miles before dumping.

Good stuff!

I like experimenting with our 186k mile Denali. It was road hard and hung-up wet before we bought it 4+ yrs and 56k ago. Gen4 LS engines are a dime a dozen around here. If I ruin the 6.2 I would love to put a 4.8 L20 in it. I have no need for all the 6.2 horsepower.

Mobil Delvac 1 ESP is both spark and compression rated, API SM & SN for spark. I bought a lot of it a few yrs ago for <$10/gal.

I don't see any rhyme nor reason for the carbon? I ran M.Delvac1 ESP 4 times. Carbon showed up only 2 times? Carbon also showed up when running the Kirkland 5w30? I don't get it?

ATF DOESN'T have detergent in it.