Mobile 1 0W-40 ??

[tramtwo]

Originally Posted by SSMickey

Beat me to it. This article is the best I have found.

Really good reading.... one day I may actually understand it.

[joeybsyc]

It clearly says in the manual, in your engine bay, and anything else factory published to run 5W30 and only 5w30... why would you want to run something else?

[SSMickey]

Originally Posted by tramtwo

Really good reading.... one day I may actually understand it.

I've read it twice and learned something both times.

Originally Posted by joeybsyc

It clearly says in the manual, in your engine bay, and anything else factory published to run 5W30 and only 5w30... why would you want to run something else?

Well, for those of us with modified engines, the factory recommendations no longer apply, so I try to educate myself so I can make an informed decision on what is best for my engine. If you have a stock engine, stick with the factory recommendations.

[wakespeak]

Car manufacturers in the US must specifically recommend only the oil viscosity used in their fuel economy tests (CAFE). Not sure what the owner's manual would say outside the US.

The LS3 engine does not run a lot of oil pressure. It appears to be relying on oil volume instead, like Buick engines used to do. So a 40 weight oil may test your seals unless it is up to operating temp (around 100 C).

[LS3 Handler]

The way I read the way the Bob guy says is that even at 75 degrees out side on a cold motor the 0w-30 is better because it flows better at lower temps so it keeps cold motor wear down but it still protects like 5w or 10w-30 at normal operating temps. So from Bob 0w-40 should be fine and because its 40 weight it will protect better than 30 weight above 200 degree oil temps.

[menendez1293]

I have used 0W-30 for the past 4 years and never had an issue but I only drive in warmer weather.

[LS3 Handler]

What oil do you use? I have been thinking of changing to 0w-30 Amsoil Signature series. I have been using Mobil 1 5w-30 high mileage.