LCP

If the 0w40 were a dyno oil, I'd be very worried about the breakdown of the viscosity modifiers for that great of a spread when run for 8,000 miles in our turbocharged cars. Are the same worries valid for Mobil One synthetic?

WClark

If I recall some of the white papers I saw on synthetic motor oils years ago, Viscosity extenders are not often used in synthetic oil. The synthetic oil inherently has a more consistent viscosity from cold to hot and will pass a wide range of hot-cold SAE viscocity tests without modification.

ryoung

... and I believe the previous message is also correct.

SteveK-O (stock!)

When I had my last oil change a couple of weeks ago, I bought Mobil 0W30 because it's all my parts store had. The last two days have been very hot here in MN (yes, this happens) and twice now my oil light has blinked on at the end of a 1 hour drive. I had oil midway in the good range on the stick. I topped it off with some 20W50 and the problem has gone away for now.

I know it could be something else, but next time I will go for 10W40 and see if I have any more problems.

Steve 98 2.8QMS

LCP

...I'm just going to have to buy it from them when I take my Audi in for service. Hopefully, they'll give it to me for only about $1/quart more than I can get it at the store. Mercedes is also using it now. If you can't find it otherwise, check with those brand dealers.

OpusK551

AND Valvoline for Audi, Castrol for VW. Go figure?

RangeR BoB

I run 15W50 Mobil1 No problems in Texas heat, still cranks fine below freezing.