Chrysler Repair: Concorde is overheating, 2004 chrysler concorde, gasket leaks

QUESTION: My 2004 CVhrysler Concorde developed an overheating problem last fall; I could bring the temp down by turning the heat and blower up on high. Recently I replaced the entire cooling system and had the engine pressure checked for possible head gasket leaks; to no avail. This 3.5 engine is still overheating. It has brand new thermostat (the one that matches what was stock in the car with the extra little hole), water pump, radiator, new fans; while we had it all torn apart I decided to replace the timing belt as well as the serpentine belt. The only thing I can possibly think of is that I noticed there is a transmission cooling line attached to the radiator. Could my transmission possibly be causing this overheating? If so, how do I check for this and then how do I fix it? Your help is greatly appreciated because so far nobody has been able to find anything wrong with the car. 2004 Chrysler Concorde, 3.5L

ANSWER: Hi Lauri,
There are not too many other causes for overheating if the engine has been checked, the cooling system replaced, and a new thermostat installed. The transmission cooler is entirely separate from the radiator, except that air has to get through both of them to cool their respective fluids. Take a look through the grille and see if you can see light coming out from the engine side of the those two units when you put a light source between the units and the engine. It could be that there are leaves/mud blocking the air channels.
Another possibility is that your brakes are dragging. After you drive it for a while, without having to use the hrakes significantly, feel all four wheels to see if any of them are too hot to touch.
The last qustion I would have is what are the symptoms of overheating, other than the gauge? Does coolant spew out of the overflow bottle? Are you loosing coolant without any signs of it?
It is possible if only the gauge is indicating such a problem that the gauge is not accurate.
Let me know if any of these possibilities exist.
PS Sorry for the delay in answering, but I just found your question in the 'pool' to which it had been referred by the other expert.
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---------- FOLLOW-UP ----------

QUESTION: Thanks for your reply. As to the symptoms of overheating, the car is fine at an idle. As soon as I get up to highway speeds of 55 and it gets up to temp it starts to overheat. I thought too that the guage could be the culprit, however, the guage does come down with the temp set on high and the blower fan all the way up. Also, the hot air gets hot enough to actually burn my legs and feet. I also noticed that when it rains and I have the heater on at all, my feet get wet! I'm not loosing any coolant because I don't allow the engine to get to the point the light comes on. There is no mud or leaves blocking anything. Also, we replaced the radiator fans because not just one, but both fans had burnt out. (That fan had high and low speeds)The new fan fan has simply on or off. I'm at such a loss here. Thank You so much for your help.

Hi Laurie,
Are you certain that the fans are coming on when the gauge moves toward the H?
The fact that you aren't loosing coolant or boiling over, would make me wonder about that gauge accuracy possibility. If it was pessimistic, and instead were to read more like mid to 3/4 scale, the same thing you observe, the needle dropping, would occur if you set it for high heat and high blower. There are temperature test gauges that read the temp via the infra-red emissions from the block/radiator/etc. that you could avail yourself of to verify exactly what is the system temp as a function of the dash gauge reading.
I recently had a similar issue with my '89 which seemed to always be riding just below the H, but the system never seemed to threaten to boil over or appear to be as hot as I would otherwise suspect based on the dash gauge. I concluded the gauge had become inaccurate, so I put a 10 ohm resistor in series with the wire from the gauge temp sensor to shift the readings downscale. Now it is behaving reasonably. But as I said the needle will rise and fall with thermostat opening up or the fan action. I would not be too concerned unless you actually see steam blow off or loss of coolant.
On the water on your feet during rain, I suspect that the drain holes for the air intake are blocked with leaves such that the water builds up to a height which causes it to be sucked into the air intake. You could remove the wiper arms, then remove the screws that hold the left and right cowl screens which will give you access to the air intake plenum. At the far right end check to see if there is a build-up of leaves/dirt that may be blocking the drain holes at the very end of the plenum.


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