Pontiac Repair: 2007 Montana van, radiator cap, head gaskets

Question
Van does not heat up in idle position but soon as you start moving it heats up great. We changed the water pump and flushed the radiator. Is there anything g else that could be wrong? We have been told that it could be the head gaskets is this true? Please help.

Answer
Hi Michelle:
Yes it could be a head gasket issue. try back flushing the heater core take the hoses off at the engine and run garden hose water both way tough both heater hoses. then re attach then and start the van and open the bleeder up on the metal pipe that runs across the fron valve cover. just crack it open so the air and water start to dribble out. once the air is expelled close it and then top off the radiator and take it for a drive make sure it doesn't over heat. let it sit cold over night take the radiator cap off top off the radiator and the over flow bottle and see hoe it is in the AM. Have you replaced the thermostat in this? It may be worth changing that. It could be pening up too soon and cuase a low heat issue.... good luck :)