Overheating problem please help!

[Nate2054]

I have a 98 Pontiac Grand Am V6 3.1


I had the waterpump replaced didnt work, intake manifold gaskets replaced didnt help the problem, i dont have milky oil and dont think its a head gasket.... the car runs until it get to normal temp 150-180 something like that... then like 2 minutes later it sky rockets and red lights then it dies out i fill it with water/coolant and it seems like it either boils or runs right out... it holds pressure it may be a thermostat if so could someone help me out and tell me pricing on a thermostat and if i can do it myself maybe a diagram or where i can get one.... thanks alot

[hywypatrl05]

well your best bet is to go to your local autoparts store and get a Haynes or Chiltons car manual (a specific book for every car) And get a thermo. there...they should only be about 12$

[Nate2054]

Ok.... if it was a head gasket would the oil definatly be milky..... and the car overheats in like 5 minutes of driving... is the water boiling that quickly... just 5 minutes ago i filled the box with water and 5 minutes down the road it was gone and overheated

[GTP Dad]

A thermostat costs between $6 and $12 depending on the type and location where you purchase it. As for replacement you will need a new gasket. Simply follow the top radiator hose to the top of the intake manifold. The thermostat is under that housing. You may need to drain some of the coolant out of the radiator to keep from losing it when you remove the housing. Remove the bolts, pull the thermostat out, clean the gasket surfaces off and replace in the opposite order. The drain for the radiator is on the side or bottom of the radiator.

Once you have everything put back together, fill the radiator and start the vehicle. Once the vehicle warms up and the thermostat opens you should see the coolant fall and you will need to keep topping it off until it remains at an acceptable level. Sounds a lot more difficult than it really is.

One tip though, don't overtighten the bolts on the housing as it can crack or the bolts will strip or break.

If you are losing coolant you may have a heater core that is leaking and causing the coolant to run out. Put some clean cardboard under the vehicle and run the car. If it is leaking you should see antifreeze on the cardboard. If you see coolant coming from the drain on the firewall then you probably have a bad heater core and you will need to replace it.

I hope this helps! Good Luck and welcome to the forum!

[hywypatrl05]

any leaks?

[GTP Dad]

Based on your description of losing coolant that fast there has to be a serious leak somewhere. Even if it were a head gasket you would not lose coolant that fast so I suspect you have a bad heater core or a bad hose that is causing the coolant to leak out that fast. If it is split or one of the hoses is leaking that is about the only thing that could cause coolant to drain out as fast as you state.

[swrobbie]

I didn't see it mentioned anywhere, but make sure the water/anit-freeze is mixed 50/50. After I changed my water pump, I drove 10 minutes to the local Uncle Ed's to flush the rest of the cooling system and the engine temp had gone way past the normal operating temp. Straight water will boil faster than water/anti-freeze mix.