What will cause my 97 grand prix pontiac 3800 series to over heat

SOURCE: 2002 pontiac grand prix over heating

Are your electric fans engaging or turning on?

SOURCE: I replaced the head gasket on my 97 Sunfire it doesn't start

If your timing is off you will have no power.check and make sure all timing mark's are correct.Some engine's are contact motor's,which mean's if your timing is off you could cause damage to valve's or piston's.Also you should do a compression test to be sure each cylinder has adequite pressure.Hope this help's.

SOURCE: Car over heating and over flow in resouvier

Whats really gunna **** you off is the part you probably need is about 5$. Inside the radiator hose is a spring loaded "switch" that supposed to expand when it becomes hot and let radiator fluid thru. Sometimes these springs freeze up and don't let the fluid thru. IE probably your problem.

SOURCE: 2006 pontiac grand prix vary little or no heat

Are you sure you got all the air out of the cooling system? Air pockets are very common problem when you do any work to the cooling system. An air pocket will do what you discribe.

SOURCE: 97 Pontiac grand am overheats as soon as it gets to running temp

If electric fans are coming on, and you have filled the system with the heater turned on high to purge it of air, even though you flushed it, I'd have the radiator flow tested (even when flushing, coolant tends to go around internal blockages, limiting its ability to work correctly) otherwise you need to begin testing from square one like you had never seen it before (don;'t assume anything you did is working) Pressure testing of coolant system, hydrocarbon test at fill opening and engine compression tests are important as well as what I mentioned above.