Had my 90k service recently, and since then, the operating temp has gone up about an average of 10 degrees C.

The needle used to hover a little above the 80 C mark, but now it seems more at home between 90 and 100.

It's been a bit warmer here the last couple days, but this is San Diego, so warmer means in the 80's as opposed to 70's. :^) Doesn't seem like it should make that much difference...

Oh, yeah, air conditioning on/off has little effect (and it didn't before).

Am I still within the proper operating temp range for the 3.8L V8?

Could a change oil viscosity have an effect on running temperature? The car is new to me, so when I did my first oil change, I had 10W-40 put in per the owner's manual. Its second oil change came at the 90k service, and they put in 20W-50.

What's the ideal weight for San Diego weather? (60-80F all year) The book's graphs don't help too much - almost all of the oils encompass the temperature range this car lives in.

I'm concerned because I'm getting ready for a trip to Las Vegas next week and do NOT want to be stuck with overheating problems.

Thanks in advance for your great advice. :^)

--Josh

1983 380SEL 87k mi