Mobil1

[trumpetr]

... actually -40C is EXACTLY the same value in farenheight, that is the numerical balance point, every 5C difference from that point = 9F difference.

-40 + 60C (12x5) = -40 + 108F (12x9), which translates to 20C = 68F (room temp)

I stand corrected, you are right.

[colo525i]

I just did my oil filter stand and oil pressure switch gaskets,and changed the oil over to rotella synthetic 5w-40. I figure its still heavy enough for everything but summer, but will be kinder on then engine when it starts to stay below freezing more often. I have had good luck with truck formula oils in older cars. I just hope my car has finally stopped leaking oil!

[Alexlind123]

I have been thinking, what difference does ambient air temperature have on the oil weight you use? Once the engine is heated up, it is always around the exact same temperature.

[colo525i]

Not 100% sure on this, but the oil would probably be hotter in hot temps (say 35c/95f) than if it were in cooler temps, as it would stay warmer in the sump. No other genius ideas, but I have noticed lighter grades would burn off in hot temps where say 20-50 wouldn't

[632 Regal]

that oil is fine year round where you live, 0w-40 is a better choice if they have it and you can exchange otherwise I wouldnt worry about it.

[Alexlind123]

that oil is fine year round where you live, 0w-40 is a better choice if they have it and you can exchange otherwise I wouldnt worry about it.

They didnt have 0w-40, they did have 15w-50 and 0w-30 though. I will put the 5w-30 in tomorrow when the engine is nice and hot.

Thanks for the help everyone!