1996 Intrepid Overheating

[mkzg]

I have a 96 Intrepid with 190k on it. Its got the 3.5 in it too. I have a problem with the car overheating. I have read other postings and am not finding any solutions. I have tested my fans, replaced the radiator, thermostat, radiator cap, and sensor. the sensor was replaced about 2500 miles ago. The car gets hot and boils over through the radiator relief tube. I can tell when the car is getting hot by having the fans on in the car, when the fans are set to blow on hot, they blow hot, but eventually start blowing cold air. The fans are supposed to blow hot air, but quit blowing hot air when the engine starts to get hot. If i stop then, and open the radiator cap, the water all boils out and once I refill the radiator, the car runs fine until the next session of this happening (usually 30 miles). I took the thermostat out and ran the car without it, and The car overheated even faster!
I am lost right now!...HELP!

[theFREAKnasty82]

try having your cooling system flushed out, it sounds like you might have a back-up or congestion in the system.

[mkzg]

I have flushed the system.....IT sstill overheats. I was wondering HOw i can check to see if the fans are good,.

[fredjacksonsan]

You haven't replaced the water pump yet, according to your description above. The impeller blades could be corroded to a point they no longer push enough water.

[syriss]

This may sound to simple, but i had the same problem and it turned out to be air in the cooling system. Because of the relationship of the radiator to the engine, if the coolant reservoir runs dry, air will get into the system. The only way to get the air out is to bleed the system using a bleeder valve located on the thermostat casing. It can take a while to get all the air out but it did fix my problem and i hope yours is as simple.

[fredjacksonsan]

Syriss, excellent point. I've had several vehicles that would happen with, and there are numerous posts on AF.

One thing about getting the air out, I've always been able to do so by parking the vehicle with the front pointing uphill, cold, radiator open, and running the engine for 1/2 hour to 45 minutes. After the coolant begins to cycle (thermostat opens) then keep the radiator filled. You'll get a lot of air to come out. Don't forget to turn on the heater after the first couple of bubbles, to make sure the heater core isn't full of air.