I Just did my "Free" Oil change at the dealer. I only had 3,600 Miles on it after 6 months, but I haven't read up on the whole, exact maintenance schedule yet, so I wanted the first oil change done early. I usually do it every 6 months anyway, no matter how many miles I have on my vehicle.
This thread made me wonder what Dexos even was? The service dept mentioned it, but I didn't know if it was a brand or a specification. So, I found this article and thought it was good enough people might want to look it over....
Do I Have To Use the Manufacturer's Oil?
I also read the article Ecohauler posted. Motor Oil 101 (through 109). That was interesting as well.
From both articles, is seems like the target is a Dexos 1 Approved Oil that has a viscosity of 10@ 212 Degrees, and the sooner it gets to 10, the better it is for the engine. Especially for an engine like mine that can sit for weeks at a time. Amd some of those weeks being in very cold weather, where it would be thicker at start-up, taking longer to actually getting around to lubricate all the parts.
Being in the cold 1/2 the year and from sitting a good amount of time as well, I'd think I'd benefit from a 10w-20, but from reading individual specs, it seems these oils go below the target viscosity of 10 when it hits operating temp. It looks like the 5w-30's hit, or stay above the 10 at the operating temps, so that's what I should be using.....
For instance;
Mobil 1 5W-30 = Viscosity @ 100ºC, cSt (ASTM D445) 11.0
Spec sheet found on this page;
http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_5W-30.aspx#
Mobil 1 0W-20 = Viscosity, @ 100ºC, cSt (ASTM D445) 8.7
Spec Sheet found on this page;
http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_0W-20.aspx#
Seems a lot more complicated then what I went thought with my 20 year ole Jeep.... Not quite sure I'm right, but that's what I got out of it...