mattarios2

So i should run a 0w-30 in summer/spring and then a 5w-40 in winter/fall?

Audi Junkie

Cold flow and cold cranking abilities diminish while an oil is in-service, so you always want to have fresh oil in for winter cold. It's another reason I change on a time schedule than actual miles. I go 4x a year, but 3x works too. 2 is fine depending on the miles and # of short trips. Just get in sync with a change after Thanksgiving but before Christmas.

I honestly don't think you need a 5w-40 at all, unless you see oil temps over +210C. Like I said, stick with GC unless you are bored or see a specific need to change viscs.

mattarios2

usually my car stays around 215 or so MAX when it's 95-100 degrees out. So it's safe to continue running GC i take it.

Audi Junkie

that yes, the oil is thinning but it is not frying and leaving deposits. That is a hallmark of GC, it's exotic methylcrylate PAO base oil. Guys at Bob's chipped in about a $1000 for lab time and our experts did a series of fractilization and wierd molecular resonance tests to find out what the heck it was made of, and it is unique. I doubt a few hours of heated operation would lead to any excess wear. Bottom line too is try a UOA. Since GC was factory-fill, I assume absolute compliance is all regards. The Porsche Approval is no joke in a 30 weight and hard to obtain in over-the counter 40 oils.