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Overheating but coolant system is pratically new

For the past 3 months I have had issues w/ overheating. 1st I thought it wasjust b/c I got too relaxed when it came to the maintenence on the car. So I.started paying attention to the car and making sure therewas water in the reservoir & radiator @ all time. Im still having overheating problem so this is everything that has been done to the car;
Its be pressure tested
Chemical tested to see if theres exhaust coming in the radiator
Ive replaced the thermostat switch twice
The radiator cap has been replaced 3 times
The reservoir has been replaced
The top & bottom hoses has been replaced on the radiator
the neck part where the radiator cap is has been replaced &
The thermostat has been replaced 3 times
When none of that made a difference & the car still overheated we took the car to get the catalytic converter off & I got a new tail pipe.
The car passed the chemical test & it held 16lbs for more then 15 mins on the pressure test, & you can see the water swirling around, so the water pump appears to be working. What were noticing is water is being dumped & overfilling the reservoir but it nots going to the radiator. Anyone else familiar w/ this issue & can give ideas or advice as to what to do?

Have you checked to see that the electric fan comes on when the engine heats up? And when the AC is turned on? Seems like you’ve been through most everything else 3 times.

Also, have you had the radiator boiled out our replaced? Buildup from lack of maintenance can internally clog a radiator and make it almost useless.


dodge stratus

Which engine?

Was the tubing from the radiator to the reservoir inspected and/or replaced?

Oops forgot to add that theres a brand new dual radiator fan on it & yes it works both with ac on & off.

What about the radiator itself? New? Cleaned?

Its a 2005 ( manufacture date 10 / 04 ) Dodge Stratus 2.4L. & yes the reservoir hose has been inspected & nothing has been done to the actual radiator yet. But this weekend we might be getting a new radiator.

Radiator as far as I know is original. And nothing has been done with the radiator. I was under the assumption that because it’s holding pressure that the radiator is good.

Nope. holding pressure is but one good thing. Not being clogged up is pretty much key to how a radiator works. If it isn’t the type you can pop the radiator cap and look inside to see the condition, you might consider removing it and looking in the outlets. Then replace it since its already out.

I believe thats the plan is to get a new radiator this week.

Classic blown head gasket. The pressure test and chemical test can miss a small head gasket leak.

When new radiator gets added to the list and it still over-heats then what will be guessed and purchased next?

I’d use the radiator money to find and pay an experienced, intelligent, thorough, qualified reputable mechanic/technician/diagnostician to pinpoint the problem. They’re out there. For such a person, this isn’t rocket-science.

Throwing money at a problem and strategically replacing every part until it’s fixed is one method of repair, but by the time you’re done you could have used the money to just buy all the parts already assembled in a different car that doesn’t over-heat. :wink:

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I have to agree with CSA. There is a chance you have a blown head gasket. Other things to look for to verify this are coolant leaks, loss of coolant even if you can’t see evidence around the engine, overheating, white smoke. A leak down test could verify this.

A blocked radiator would not be my first guess. Radiators have lots of interconnected tubing. One blocked tube would not likely cause a significant impact. You could feel the upper hose, it should be significantly hotter than the lower one or you could try a flush, but I think you are wasting more money.

I too, would stop using a shut gun approach to fix this.

I have never heard of having a radiator boiled out.

What is that ?

Dunk the radiator in a hot-tank with a caustic solution to wash out the accumulated crud. Usually overnight. Used to be a standard procedure with copper-brass radiators.

Not sure anyone does this anymore since it may melt plastic tanks and their seals.

Check the color/smell of the transmission fluid.

If color is dark and it has a burnt odor, it means the transmission is overheating.

Why would that cause the engine to run hot?

The transmission fluid is cooled by a cooler located inside the radiator.

So if the transmission is overheating, it can cause the engine to overheat.

And vice-versa.


Thanks Mustangman.

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Nobody boils out or rods radiators anymore.

With the plastic tanks and aluminum cores, they’re too fragile.



My car radiator is plastic.

Under what conditions does it overheat? Around town stop and go driving, idling while waiting in a fast food line, freeway driving? What are the symptoms when it overheats? Loss of coolant, steam? Dash temp gauge going into red zone? Engine performance problems?

A radiator shop could flow test your radiator for you, give you an idea whether it is clogged or not. You could get a diy’er idea yourself if you had a known good radiator kind to compare with. With the engine off and cold, fill the radiator & leave the cap off, remove the bottom hose, and time how long it takes for all the water to drain out. A radiator shop could measure any unusual pressure build up too, indicating a head gasket problem.


You can get the engine up to operating temperature, shut it off, and then take an infra-red thermal gun and point it at the cores on the back-side of the radiator to see if any are plugged?


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