Heater Always On:

[chilkoot]

I didn't even try to turn the climate control on, fearing that the heat was a defense mechanism of an overheating car that I was trying to limp home. if the a/c system is off is the car supposed to be pumping heat out of the dash vents?

also, the whole way home with cruise control set between 65-70 the temp gauge barely went past the first notch (new synthetic oil). I remember the '90 sitting in the middle of the gauge. Driving it that morning to the auto parts store (10k+ old dino oil) the temp seemed to fluctuate between the first and second notches, depending on my speed. those temps seem way too low, bad water pump?

[glenmore]

If the car does not reach operating temperatures, this is typically a malfuntioning thermostat, which is a cheap DIY fix. Fix as soon as possible as the thermostat on my Mercedes was doing that, making the engine run to cold, then it finally failed in the closed position and I overheated.

As to the hot air coming out of the vents when no AC or HEAT is on, others have had this complaint. I sometimes have this problem. I am guessing the problem is the servos that control the flaps are getting old and they don't close and open as they should. When this happens, I turn on the AC and then turn it off. Somehow this moves the flaps enough to deflect the hot engine compartment air.

glenmore

1990 ls400

[chilkoot]

awesome, exactly the info I was looking for. thanks.

i'm not worried about the heat coming out of the vents, so long as it's not an overheating defense mechanism. i just wanted to make sure it wasn't an engine safety issue.