Assuming the cooling system appears to be full, it sounds like air trapped in the engine block. This is a very common problem. Did you use the bleeder valve by the thermostat to relieve trapped air? Even if you did there may be air trapped further down. It may require draining and refilling. Some people have had success doing this with the car facing uphill, allowing the air to come up out of the system more easily.
07 Pontiac grand prix no heat replaced themast water pump flushed it out does not over heat
2007 Pontiac Grand Prix Base
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Maintenance & Repair
My fans work my hoses are hot and I have fluids and my gauge still in the red zone and no heat even on full blast just cold air I did change thermostat someone please help me
2004 Pontiac Grand Prix GT1
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Maintenance & Repair
I just recently bought a 04 Grand Prix the heat does not get hot just like Luke warm (sometimes) the blower works fine & we changed the thermostat today so it isn’t that the hoses are hot it is NOT...
2004 Pontiac Grand Prix
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Maintenance & Repair
My Grand Prix GTP doesn't seem to want to heat up. There is no heat coming into the passenger cabin from the heater core and my temp gauge never gets up to the 1/4 mark. I've changed the thermostat,...
2002 Pontiac Grand Prix GTP
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Maintenance & Repair
can not find any leaks anywhere no wet spots after running car put antifreeze in jug and run car check next day and its empty have little heat when car is ideling soon as i drive it gets cold oil loo...
2005 Pontiac Grand Prix Base
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Maintenance & Repair
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