Heat Problems????????

thebeachbum33 · Post by **thebeachbum33** » 24 Jan 2004, 06:47

I have a 89 740GLE with 231000 miles, while driving in the past cold snap(-10 to 10 degrees) in NJ my car's heater failed. It would get warm when the engine idled but as soon as I took it above 50mph the engine would cool(indicated by the temp. gauge) and the heat would blow cold air.

Since the daytime temps have been above 25 I have not had any problems, is there something I need to replace? This has never happened to me in past winters.

Thanks

LaRy · Post by **LaRy** » 24 Jan 2004, 08:19

The water thermostat is probably jammed, not closing as it should. When it is warmer outdoor, it is closing enought, but when it is really cold and you drive your car, the water pump is working better and speed wind is cooling so much that water temperature is going down.
It is actually easy to check this. If the big upper rubber hose to the cooler is hot before the motor temperature has reached normal value, the thermostate is broken. As long as the temp gauge is telling you that the motor is cold, it should pass very little hot water through the cooler.

Volvord · Post by **Volvord** » 24 Jan 2004, 11:31

Yes it sounds like your thermostat is not closing. This is relativly common with all cars. The fix is to replace the thermostat.

camper guy · Post by **camper guy** » 29 Jan 2004, 11:47

I had this same problem two weeks ago, (I'm in New Hampshire). I changed the thermostat and now the heat is incredible. I would flush the coolant too if you haven't done that in a while. My car was incredibly maintained by the previous owner, but the coolant was turning brown from age. Flushed and replaced it with the new thermostat and it's great now.