What is wrong with the heat in my 2002 Pontiac Aztek?

[designkidcom]

My family has a 2002 Pontiac Aztek, and the heat works occasionally. When the vehicle is in motion the heat works fine, but when you stop and idle you get nothing but cold air. The temperature gauge then shoots up, and a light showing hot temperature displays. Any ideas on what's causing the problem?

 

[Griz]

The vehicle in motion gets outside airflow and when you stop there is no flow. This indicates that the heater fan is not working: check the fusebox to see if the fuse is intact. The temp-rise sounds like the water-coolant isn't being propelled through the engine. Check for a broken-missing belt..defective thermostat..insufficient coolant level. You may just need to add some antifreeze.

 

[chris v]

It sounds as though you need to add water. When you idle, the little amount of water you have in the radiator is resting and not circulating, therefore the engine overheats and you have no water in the heater core to get heat from. When you move, the water circulates and both problems go away. If you check the water and it is full, then your thermostat is sticking. These are the ONLY possibilities, but realize that there may be something leaking to make the water low. GOOD LUCK!