Originally Posted by bluzman

Here's more anecdotal data. Had to go to a place near Phoenix last Friday, about 525 miles each way. From northern Santa Barbara county, that means most of the trip is a boring run through the desert on the I-10. The temperature was over 100 by the time I hit Palm Springs and stayed between 100 and 105 the rest of the way (about 250 miles). There are several long uphill pulls in that stretch (Indio to the Chiriaco Summit and from the Colorado River nearly all the way to Quartzite are 2 examples) so I figured I'd find out whether my Z has issues. In the heat, I mostly ran between 75 and 85 MPH (except for a few short bursts at higher speed while dusting off folks who thought they wanted to play but who found out they weren't in the same league with a 370Z). BTW, the A/C was on the whole time.

Bottom line is that the oil temperature never got above 238 and then only on long pulls. On average I'd guesstimate that the oil temperature ran around 225. Like I said, this is just my experience with my car and my driving. I make no claims about broader implications. What I will say is that I personally am no longer concerned about oil temperature problems. YMMV.