Originally Posted By: GMBoy
Originally Posted By: TiredTrucker
My 2006 Cadillac CTS 3.6L gets a 10w30 conventional year round. GM said it had to have M1 5w30. Still doing great. And that is in the upper midwest. I would jump on a 10w30 year round living in southern Cal in a heartbeat. The Lucas.... never. And for high mileage needing a heavier oil like a 40w? Gonna have to tell my 12.7L Detroit engine with 688,000 miles on it that a 30w won't work. It never got the memo. It uses about 2 qt in 22,000 mile / 500 hr OCI's and UOA's look as good as they did below 100,000 miles on the engine.
You do realize that engine requires an oil meeting GM4871 spec - which is synthetic oil. Atleast make sure you are using a DEXOS certified oil in that car.
I think the early GM brand Dexos was synthetic blend ? It may now be full synthetic ? We have always used Mobil synthetic Dexos in our little Chevy Sonic . Except we got 4 free oil /filter changes with the car . Guessing they used ACDelco filters & GM oil ?
God bless
Wyr
