Originally Posted By: Neil_A
Well that explains my confusion when visiting the GM dealers quicklube for a full syn change. When I told the rep I wanted a full syn oil change he asked which one, Dexos 2 or Mobil 1? I said Mobil 1 it's the best and is Dexos licensed. He then stated that he gets his changes for free and he picks Dexos 2 over M1. The Dexos 2 storage container states full synthetic, and the rep says he's seen Dexos 2 motors torn down and they looked better than motors ran with the mighty M1. For my wife's Trailblazer we went for the cheaper Dexos 2 full synthetic, most likely made by Mobil anyway.
You do know that Dexos 2 is not the same thing as the Gen 2 Dexos 1. Dexos 2 is the GM European and Diesel Oil specification and came out the same time as Dexos 1. As far as I know the only vehicles in North America requiring Dexos 2 are the small Diesels in the Cruze, Canyon/Colorado and specified as "ok" to use for Track use in the LT1. The latter likely just because it is a heavier oil that carries a GM spec.
Dexos 1 is xW-20 and xW-30 FE oils and Dexos 2 are xW-30 and xW-40 oils with an HTHS of 3.5 or better.
If I went into my local dealer and asked for Dexos 2 they would be giving me the European/Diesel spec oil and not Gen 2 Dexos 1 which is what I suspect that GM quicklube is doing. Especially if he is saying he has seen engines torn down already on Dexos 2 and Gen 2 Dexos 1 just came out recently.
However, interesting that he states he is seeing better wear on Dexos 2 oils.
I have two vehicles that specify 5W-30 and Dexos 1. One is now out of warranty and I am toying around with the idea of running a European spec oil in it since it is a DI and shears oil pretty badly. UOAs haven't been bad but not great either compared to a non-DI car and wonder if a thicker higher HTHS oil would be better.