How hot is too hot?

jellyhead · #1 (**permalink**) 08-11-09, 04:51 AM

My 2006 XLR sometimes will get up to about 230-240. Is this too hot and is it normal? I've read some reviews on the XLRs and this seems to be a common problem. The temp is usually pretty low maybe in the 180-190 range normally. If I'm doing mountain driving in slow traffic where my speed is under 50 mph and the outside temp is over 85 it starts running hot. I never saw the temp warning but 230+ just seems too hot.

deadringer · #2 (**permalink**) 08-11-09, 01:24 PM

What city are you driving it in? whats the outside temp?

ewill3rd · #3 (**permalink**) 08-11-09, 09:09 PM

If you are going slow the temps will get up to that range. The thermostat opens at 180-ish, the fans (without a/c) don't come on until about 225-ish.
On a steep grade the engine is working hard and in slow traffic it will be pretty much the same.
I have seen a few fans go bad though so if you are really concerned have the fan operation checked.

jellyhead · #4 (**permalink**) 08-12-09, 04:16 AM

This was on a recent trip to Tahoe and Reno NV. I was driving south from Oregon and there are several long grades around Mt. Shasta where the freeway was down to one lane. Also from Virgina City to Reno it got up to 230-240. The outside temp was about 97 on the freeway and the temp kept climbing until I got to the top of the grade. The needle was almost at the mark midway between 220 and 260. It seemed that it surely would have overheated if the grade had lasted much longer.

ewill3rd · #5 (**permalink**) 08-12-09, 07:52 AM

There are a few places like that where it is unavoidable. I drove through Death Valley one time and it was 113 degrees outside. It is a long grade like that and cars were lined up on the shoulder trying to cool down.
I even had issues driving up into Denver in cooler weather because of some of the grades.
Keep an eye on it during normal driving.
Extreme situations like that make it hard to judge what the car should do because that kind of a load really pushes those system to their limits.

ccclarke · #6 (**permalink**) 09-15-09, 11:21 PM

Your car is operating as expected. Too hot is when the fan duty cycle is @ 100% and the coolant temperature still climbs.

The cooling fan duty cycle begins when the coolant temp reaches 187, and ramps up to 100% at 235 degrees. Above an oil temp of 302, the fan is commanded to high speed, the same applies when the transmission oil temperature reaches 270 degrees. When the vehicle is shut down, if the engine coolant temperature is >235, the fan will go to 50% (low) speed; if the temperature drops to <230, the fan shuts off. The fan will automatically shut off after 2 minutes regardless of temperature when the vehicle is shut down.

CCC