Oil Type

[ThomasJ2895]

I have a 2005 GP and the owners manual says to use 5W-30 even at temps well above 100F. They specifically state not to use 20W-50. Who are they kidding? Since when is 30W oil acceptable for temps over 100F? They either are smokin something funny or purposely want the engine to spin as free as possible for fuel economy standards. Never have I ever used 30W for anything close to 90F+. I'm more interested in protecting my engine rather then getting 1 MPG better mileage.
Does anyone have comments or are running with anything heavier?
Thanks,
Tom

[wlkjr]

It's your car.

[tblake]

20w50 is some thick oil Tom even for summertime. What motor do you have? I know series II 3800's recommend 10w30 year round.

[BNaylor]

Originally Posted by ThomasJ2895

Since when is 30W oil acceptable for temps over 100F? They either are smokin something funny or purposely want the engine to spin as free as possible for fuel economy standards. Never have I ever used 30W for anything close to 90F+. I'm more interested in protecting my engine rather then getting 1 MPG better mileage.
Does anyone have comments or are running with anything heavier?
Thanks,
Tom

I think you are confused on oil viscosity and temperature ranges. It is perfectly acceptable. Or I must be in big trouble is that is the case since the temperatures exceed 100 degrees F frequently in my area.

You should use what GM recommends for the particular engine.

[ThomasJ2895]

Thanks for the replies...I'll stick with what the manual says...
Appreciate it.
Tom

[tblake]

Good thinking Tom. Not to mention if you do have a mechanical motor issue, your car will more than likely still be covered under warrenty.