Asked by Nov 24, 2010 at 03:26 PM about the 1998 Pontiac Grand Prix 2 Dr GTP Supercharged Coupe

Question type: Maintenance & Repair

I've changed the water pump, thermostat, radiator, and the radiator cap and the car still overheats because water is boiling out of the reservoir is this because my head gaskets are blown? there's no water in my oil and i changed my spark plugs and there was no oarnge film on the old ones.  

8 Answers


the only thing I could guess is that there could be a restriction somewhere in the system, causing an increase in the pressure allowing the radiator cap to release coolant into the reservoir. did you check to make sure the radiator and heater hoses are not pinched or kinked. One of the radiator hose has a spring inside to prevent the hose from collapsing, so it is also possible that the hose with that spring might be bad. cooling system flush may help

3 out of 3 people think this is helpful.

Danny, I am somewhat using your advice to fix my overheating problem. We literally stripped everything down and replaced it in all to still overheat. I'm wondering if you have a suggestion as to where the restriction might be because it is not with the spring issue. My original post is on the Sebring forum. Thanks for your help!

2 out of 2 people think this is helpful.

the other things I would consider checking verify that the radiator cap is the correct pressure rating for your car correct coolant/water mixture it may not be a bad idea to check to see if the engine coolant temperature sensor is working correctly missing, loose, damage deflector and/or seals that maybe used for a radiator and/or any add on accessories that could block air flow to radiator whether the cooling fan motor is getting power and that they are work and the blades are not damaged

1 out of 1 people think this is helpful.

you could have a cracked head that leaks exhaust into the coolant and builds pressure,you won't see any oil .

3 out of 3 people think this is helpful.


1 out of 1 people think this is helpful.

did you bleed the air pockets out of the cooling system?

4 out of 4 people think this is helpful.

If you havent yet change the plastic coolant elbows under the supercharger and alternator. could be cracked and leaking causing issues. $3 at autozone and orielly auto

2 out of 2 people think this is helpful.

air air air there is air in your system I guarantee it I have a 2001 Grand Prix GT coupe I'm going through the same problem right now I replace the head gasket set radiator the hoses the heater core the water pump everything and the air is still making my engine overheat like crazy and other times it doesn't overheat there is air and its a pain in the ass to get Out. there is a bleeder valve on top of your thermostat housing but it takes a lot of times to get it out good luck

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

  • Overheating 1 answer

    I have replaced radiator over flow tank and the thing that opens and shuts it is still overheating is it the head gasket or maybe it needs s flush I can't afford to have someone fix it or get a ne...

    2005 Pontiac Grand Prix


    Maintenance & Repair

  • overheating 2 answers

    my car keeps overheating, I've already replaced the cooling elbows, thermostat, and the water pump. However the over heating keeps reoccurring after ten minutes of driving it shuts down. Both the co...

    2007 Pontiac Grand Prix Base


    Maintenance & Repair

  • car overheating 1 answer

    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


    Maintenance & Repair

  • Overheating heat stop working 5 answers

    I have a 2008 grand Prix and my heat stop working and my car is overheating anybody know what's going on

    2008 Pontiac Grand Prix Base


    Maintenance & Repair

  • Overheating 20 answers

    I put alumaseal in my car last week because coolant was leaking but it wasn't on the ground. But my car is still overheating. Is it possible that I have a blown gasket

    2001 Pontiac Grand Am SE


    Maintenance & Repair

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 2,919 nationwide Grand Prix listings starting at $1,995.


Search Pontiac Grand Prix Questions

Pontiac Grand Prix Experts

#1 Js08016
Reputation 4,120
#2 Tom Demyan
Tom Demyan
Reputation 2,770
#3 munron
Reputation 2,150
View All

Related Models For Sale

Used Pontiac Bonneville
542 listings starting at $3,699
Used Chevrolet Monte Carlo
17 Great Deals out of 1,380 listings starting at $1,995
Used Pontiac Grand Am
1,254 listings starting at $1,593
Used Ford Mustang
390 Great Deals out of 47,511 listings starting at $1,800
Used Chevrolet Malibu
864 Great Deals out of 81,222 listings starting at $995
Used Chevrolet Camaro
146 Great Deals out of 32,614 listings starting at $1,729
Used Pontiac Firebird
6 Great Deals out of 745 listings starting at $2,500
Used Honda Accord
768 Great Deals out of 88,118 listings starting at $1,150

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
13 Great Deals out of 437 listings starting at $1,995
2007 Pontiac Grand Prix For Sale
410 listings starting at $2,999
2006 Pontiac Grand Prix For Sale
459 listings starting at $3,500
2005 Pontiac Grand Prix For Sale
376 listings starting at $3,991