2002 Dodge Intrepid overheating problem

I have a 2002 Intrepid ES with a 3.5L V-6 with 264,000 miles on it. I have recently had the timing belt and water pump changed. Three weeks later I am driving home and the temperature gauge starts climbing. This is the first time this car has ever overheated. Well, I call my buddy who is a certified mechanic and he tows the car to his shop. I have him check the water pump to make sure it hasn’t prematurely failed. He tears the front of the engine down and inspects the pump. He finds nothing wrong with the pump but he discovers the timing belt tensioner has failed and it has caused the engine to jump time, I tell him to go ahead and replace the tensioner. After he put the engine back together he started it and it ran cool while it was sitting at idle for about 45 minutes. Then he took it for a test drive and it overheated again. He checks the thermostat and finds that it has also failed; he replaces that also, still overheating. New radiator hoses, upper and lower, new radiator, new thermostat, new water pump and it still overheats. He put dye into the coolant to check for a blown head gasket and it tested negative for a blown gasket. The exhaust doesn’t smell of burning coolant or producing white smoke. My mechanic friend and I both have run out of solutions and all of these repairs are draining my bank account. Any ideas? I’m out of them…


Are all of the fans working correctly?

Have you replaced the radiator cap?

Did your mechanic buddy use quality parts?

I’ve actually had overheating CAUSED by a new faulty thermostat

Are there leaves and debris blocking airflow through the condenser?

How is your radiator . . . any chance it’s partially plugged?

I’d change the thermostat again and make sure it isn’t in backwards, if it’s possible to do so on this engine. Also, a 12 year-old radiator could be clogged–you could feel it for hot and cold spots if you can get your hand in there.

These are good engines and not prone to many problems, unlike the 2.7L. They are not known for blowing head gaskets, but it’s not impossible. I know you’ve checked with dye, but it may be worth checking the coolant for combustion gases–you could have a leak that is only occurring under acceleration but not at idle.

How high is the temp gauge going?

maybe you still have air in the cooling system ,there is a bleeder screw on the engaine where the upper hose goes

As stated earlier, all of the parts listed have been replaced. New radiator, upper and lower hoses, radiator cap, water pump, timing belt, thermostat, engine and heater core and hoses have been flushed twice. The entire system has been bled a dozen times. It has been dye tested for combustion gasses twice. It stays at a normal temperature while sitting in one place and the cooling fans turn off and on like they are supposed to. The moment you start driving it the temperature begins to move. My buddy is going to yank the thermostat and try to see if the problem is still there.

This is a tough one. It sounds like you’ve already done all the obvious things. hmmm …

Good idea to test the thermostat by putting it in a pan of water on the stove, with a thermometer, and making sure it opens at the correct temperature. Also make sure it opens to the full dimension spec’d by Dodge. If Dodge’s shop manual for the car says is the thermostat is supposed to open 0.8 inches at 220 degrees (or whatever it says), make sure by visual inspection that it does so. Double check the orientation at install also. Besides the correct version of what is inside and outside, a thermostat sometimes has a required up/down orientation.

When I’m working on the cooling system of my own cars I always do this little experiment. With the coolant full and cold, open the radiator cap. Start and idle the engine. Feel the top radiator hose. When it gets hot, look inside the radiator and verify there is a good flow coming in from that hose. If the radiator cap is situated so I can’t get a good view, I’ll remove the top hose and let it drain into a bucket. I just want to verify there’s a good strong flow when the thermostat opens. Uf there isn’t that’s a clue the thermostat isn’t working, or the water pump is faulty.

I think you already know, but it’s also possible the engine has been seriously damaged by the timing belt tensioner fiasco. Best of luck.

I would check the valve timing again. As a long shot, is it possible the fans are running backwards? I saw this happen on a 92 Chrysler minivan that had been hit in the front corner and the fan wires were damaged. The Chrysler dealership who repaired it had crossed the fan wires when they spliced it together. At idle and slow speeds the car ran fine with the fan pushing the air forward through the radiator, at 60 or better the air coming in would overcome the fans but at 45-50 there would be no airflow and the car would boil.

Should I submit this for a “stump the chumps” skit, or what?

Ism not sure if you have fixed this problem yet, but I had the same problem. You will need to replace the plastic overflow tank. These tanks have two chambers and they leak internially. Hope this helps

Aftermarket overflow tanks for this application can be problematic. Your best bet is one from the dealer.

You guys realize you’re commenting on a discussion that hasn’t been active since Sept?

@oblivion : Yes!

I’m just sayin’ that the OP is likely long gone and has probably fixed the car by now, not that we’ll likely ever know what the issue was…

Having the sane issue with mine, June 2020, any definite answer for the problem? 02 Intrepid R/T


Unfortunately, I never did figure out why this car was overheating. A lot of people have told me that it is a problem with the overflow tank. I ended up trading this car in for a new truck. Hope this helps and good luck finding the solution to your problem. I really liked that car but it had extremely high miles and began developing more problems than I could figure out.

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