I recently purchased a 2002 Pontiac Aztek. It had a few problems when I bought it, most of which I had a mechanic fix. He suspected it did not have a thermostat in it since it did not get as hot as it should when idling and ran abnormally cool at highway speeds. However, whenever the motor was fairly hot the heat worked just fine. Perhaps it was a bit subpar at highway speeds when the motor was cooler, but like I said if the temp gauge read at least about 1/4 of the way up I had decent heat. I did not think it would be a problem for me. Well now the heat sometimes just simply does not work at all. It just blows out cold air. The motor is running at a warm temperature when this is occurring and sometimes is even hotter than it usually is. It seems to be random when it quits working but it is happening about half the time I drive it now. I know if the thermostat is missing that can't be the reason, but I'm wondering if it had a malfunctioning one would that even be possible to be the cause? Or am I looking at a heater core or heater control valve problem? Those are just some of my guesses, thought I'd look for help on here. By the way, coolant level is perfect.
No Heat! Help!!!
- Thread starter jmcc03
- Start date
Zimgxp
New member
Have you put a thermostat in it. The temp should be at least at the halfway point on the gauge with a 195 stst in it. Without a stat the vehicle might overheat because the coolant moves too fast through the system. You need to verify the actual temp with a scanner or an ir thermometer. Put a stat in it and bleed the air out and see what happenes.
Thanks for the response. No, I have not installed a thermostat. I wasn't sure that would fix my immediate heating problem. The actual engine temp has been verified with a gun though. As I said in my previous post, it typically runs a little on the cool side. Although when it is going through a "no heat phase" it runs hotter than it usually runs, but that's still safely in the operating range.
Let me also add, this is not my personal car. I bought it in order to try and flip it so I don't want to fix anything that I don't feel like I have to. If a thermostat would fix it, I have no problem spending the money. I just hate to throw money at it when I'm unsure. If it doesn't have a thermostat in it at all, which was a mechanic's original opinion, I don't see how adding one would relate to this problem at all. If it does have one malfunctioning, I'm just wondering if its possible for it to even malfunction in a way to cause the symptoms that mine has. Every car I've had that has had a broken thermostat either overheated as soon as it broke or never got hot at all. Is it even possible for one to be halfway broken or something?
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Zimgxp
New member
It could be stuck open.
