Have checked your oil dipstick and oil cap? If it looks like chocolate milk it's either a blown head gasket or cracked head. Also, not sure if you know or not but you have to bleed the system when flushing out and replacing the coolant. Google year.make model and engine procedure for bleeding cooling system
Most common problem is air trapped in the system. You could also have a shop pressure test the system to see if there's an internal leak.
I drained and flushed the radiator on my 01 Grand Prix and it still overheating
2001 Pontiac Grand Prix
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Maintenance & Repair
Put brand new water pump and radiator and car still overheating
2002 Pontiac Grand Prix GT
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Maintenance & Repair
we bought my son a car that needed a water pump replaced. We have replaced the water pump and now the car is overheating with smoke coming up through the console. It is also lossing it's get up and go...
2000 Pontiac Grand Prix GT
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Maintenance & Repair
Replaced water pump. Car overheats unless I am running 70 mph, I let car run untill temp gage 1/2 way and the fan didn't come on. Does that mean the fan is bad? Please help
2005 Pontiac Grand Prix
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Maintenance & Repair
2006 Pontiac Grand Prix still overheating after a new water pump and thermostat fans are working and radiator is fine, and the car won start now after overheating
2006 Pontiac Grand Prix Base
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Maintenance & Repair
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