I have a grand prix 1999 And im having overheating problem thermostat and water pump been changed doesn't smoke or anything but temp gauge goes to red and also doesn't blow any heat just cold air

Asked by Nov 17, 2015 at 03:12 PM about the 1999 Pontiac Grand Prix 4 Dr SE Sedan

Question type: Maintenance & Repair

11 Answers


I suspect your radiator needs replacing. Did you flush the engine and radiator when replacing the water pump? If not, do that too. I would also make sure the cooling fans are working.

Best Answer Mark helpful

Yes the raidator was flushed and yes the cooling fans are working

Any other suggestions


Make sure all the hoses are good and that one is not collapsed. A new radiator should fix it unless you have a bad head gasket. Try adding Redline Water Wetter when you put new coolant in.


What brand of cooling flush did you use was it Prestone Super Radiator Flush ? If not try that brand it is really some good stuff.

Ill try that and i hear like a air sound but cant pinpoint exactly where its located and i used some cheap antifreeze because when I needed some I was only near a gas station


The air sound you hear does it sound like a vacuum leak ? If so spray some carberator cleaner around the area you think the sound is coming from if engine revs up or changes in sound the leak is in that area.


The radiator cleaner in a bottle works fine if your engine and radiator are fairly clean but for really dirty engines you should get something like this ---- http://www.amazon.com/Prestone-AF-KIT- Flush-Fill-Kit/dp/B000CCFY5W/ref=sr_1_1? ie=UTF8&qid=1447811373&sr=8- 1&keywords=radiator+back+flushing+kit


If the cooling system was flushed and with the new thermostat and water pump there's really no reason to think there are faults with the cooling system. Most likely there is air trapped in the system that needs to be bled out. This can be difficult to do on some cars and may require the assistance of a shop with the proper vacuum equipment to draw the trapped air out. I have heard that filling the system with the car parked facing uphill makes it easier to bleed the system but I haven't actually tried that. There is a bleeder valve near the thermostat that you use to release the air from the system. As long as there is air in the system the coolant will not flow properly and you will have overheating problems and lack of heat in the car.

@munron i bled it already im just looking forwRd to putting in a shop cuz no mechanic i went to can solve the problem all said different things hopefully it isn't anything serious


Let us know what they find. I'm still betting it will turn out to be air trapped in the system. It's sometimes very difficult for a do-it- yourselfer to get the air out even following proper bleeding procedure.

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