Hot Intrepid

My Mom's 97' Intrepid overheats while driving.I have replaced the thermostat,and it still overheats. I really don't think the water pump is bad,because it runs cool on the highway. somtimes it might go 3/4 on the highway and in town. and once you park it and shut the motor off,and a few seconds later(POOF) here comes the water running out of the overflow hose on the tank.?????????? Could it really be as simple as the radiator cap?????
P.S. The fans all work fine.

[traskin]

It could still be the thermostat. I had a problem with another car tha would overheat in the city, but run fine on the highway, but that was because of all the air blowing over the engine at highway speed. Better to start with the simple "could be's".

[indyram]

1. First make sure you have enough coolant and that it isn't really broke down.
2. Then when the engine is hot check the upper radiator hose and see if it is hot. That is the best way to see if your thermostat is working. If it's cold or warm, but not hot to the touch the thermostat is likely not opening.
3. Make sure the thermostat is in the right way, it can go both ways and if it's backwards it won't work.
4. Check the oil and make sure it's proper level and not bad.
5. When the engine is hot, with it NOT RUNNING feel around on the radiator and see if there are any spots that are a lot cooler than the rest. This will let you know if there are any cores that are plugged and not allowing circulation. If that's the case do a coolant flush, might not be a bad idea to do one anyways.
6. If all else fails until this point I would just go ahead and change the water pump. The '94-'97 models are notorious for this problem. Trust me I know I did 6 in 8 months, after the first they were all warranted.

[howardstern]

Water pumps don't seem to go all at once but instead they just get weaker and weaker. It may flow enough water at highway speeds but not at idle. I had an overheat problem in my buick and I thought it was the thermostat so I changed it and even later ran it without one at all. I'm so sorry I didn't change the water pump! One day on a 100 mile drive I blew the head gasket and with only 90,000 miles, that was pretty much it for the engine and the car!

[Repazentin_269]

i can probley tell u the problem right off the top of my head check both your fans and make sure hey both run both hi and low u probley have to replace the conecters under the fan i just did it to my car like last month. hope that helps make sure they run all the time mine kicked in and out so gl might be the cap also