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Dodge-Plymouth Neon Overheating

90 messages,  Last post on Feb 20, 2013 at 5:10 PM

You are in the Dodge/Plymouth Neon Forum.

What is this discussion about? Dodge Neon, Plymouth Neon, Dodge Neon SRT-4, Engine, Sedan

Messages Page 10 of 10

#88 of 90 Re: 99neon that overheats [rickscafe1] by toniol

Jan 25, 2012 (1:58 pm)

Replying to: rickscafe1 (Jan 25, 2012 12:01 pm)
Rick that sounds very very logical but can you give me some insight on why would the coolant reservoir would fill up and it seem like it purges it self... I was reading another here stating that there is a coolant hose that comes from the heads if I am not mistaken that goes to the heater core that cool be doing some leaking, however could there be air in the system? Coolant in the reservoir seem like it boiling but no high temp gauge displaying. I did release the pressure the cap and had it like 98% but when I press back on the cap the reservoir would seem to boil but I think it air is being expelled to the reservoir. Replace the thermostat a second time still the same. I was think about going to get a pressure test for air in the system and trying to locate this leak it only leaks when I drive a while. Insight please and thanks for you findings on this issue. I was leaning toward the temp pressure switch or the item you mention just that I have go out and buy it.....
 
THANKS!

#89 of 90 Re: 99neon that overheats [toniol] by rickscafe1

Jan 26, 2012 (7:17 am)

Replying to: toniol (Jan 25, 2012 1:58 pm)
Okay when a liquid overheats it expands and there is the hose from your thermostat housing to the coolant reservior. When the liquid expands from overheating it causes a lot of pressure. Ideally the cooling systme runs at 16 psi but when it overheats the pressure goes up higher and the radiator cap is supposed to react to that presssure and open so that the coolant goes into the reservoir. Now the Neon is supposed to run on a 50/50 mix of water/coolant. If you do not have enough coolant in it it will boil at a lower temperature and expand at a lower temperature. Now if you add more coolant when the reservoir is full you'll get more out when it boils again. THe overflow reservoir is just that an overflow reservoir. I do not know how you're suposed to get the overflowed coolant from the reservoir back to the engine. Some people say that the coolant willl be sucked back in. Now that is the case with a degausse bottle but the overflow reseroir we have on the neon is not that. The problem isn't that the reservoir is full or not full the problem is that your car is overheating in the first place because only overheating will fill the coolant reservoir. Now I chased this overheating all around my car I thought the radiator leaked because I saw a plume of smoke coming from it I thought. Turned out it was a small piece of hose that was not the correct length behind the intake manifold next to the thermostat housing. I had thought that is was leaking then overheating becuase of this when it was actually overheating causing it to leak. That's what I think is happening to your car it is overheating causing it to fill the reservoir. But why is it overheating? FIrst thing to check would be the thermostat they go bad about every year or two depending on the mileage you put on the vehicle. IF you do not have an automotive manual for your car I suggest you get one. They are sold in most auto parts stores. There they have a list of symptoms and possible causes for those symptoms that can help you narrow down your search for the problem. With mine I was getting a code saying that the coolant temp sensor was faulty. I didn't have a scan tool at the time so I had to take it to the local autoparts store to get it scanned for free. I scanned it because the check engine light came on that means that there is a code in the computer for you to look at. Now I had heard these sensor go bad or become defective so I bought a new one. After that the gauge read hot all the time. So it looked like now it was the gauge the whole time but when it overheated before I ever replaced the sensor for the gauge the gauge read accurately so I unplugged the new coolant sensor and plugged the old on back in. The same thing happened the gauge read hot. So now I know that the problem lays between the gauge and the sensor. That means the wiring in between had a short. Now the reason I replaced the sensor was that it was not telling the cooling fans when to turn on. When I looked for the short I started taking the old crumbling conduit that protect the wires in the engine compartment off. I started at the beginnnig at the plug for the sensor it wasn't until I had moved further and removed more that I found the problem. I was going to plug the sensor back in when I saw bare copper at the very end of the plug where the wire was sticking out. It has 3 different wires to it the sensor does and all three were wrapped around each other without insulation causing it to short out and cause the gauge to read hot at all time. Before I replaced the sensor it was probably wrappeed around enough so that 2 of the wires were wrapped together causing to short out and not turn the cooling fans on. Like I said that sensor is in a difficult spot and you have to bend and twist the plug around slightly to plug it into the sensor. Apparently I twisted it too much or two far when I replaced it but it was already partially twisted from whoever worked on the car before me because it was twisted at one full turn to get the wires to wrap around like that when I had only twisted it a little bit.

#90 of 90 Re: 99neon that overheats [rickscafe1] by no2498

Feb 20, 2013 (5:10 pm)

Replying to: rickscafe1 (Jan 25, 2012 12:01 pm)
anyway for you to post a pic of the wires and sensor
if you send it to my email put neon pic so i know what it is for
 
as for the head gaskets
thinking this is the same thing as the olds bumpers that fell off
two metals that dont get along together
same thing for the ground wires
 
all the relays are the same trade the fan for the horn beep the horn if it works its good for the horn anyway in case it was over heating it
 
thanks for the Forum
 
the car i have is 96 neon with only 51000 miles on it
just had the head planed today it did not take all the pits out of it
now i wish they still made copper paint like they used to
 
john

Messages Page 10 of 10

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