Overheating -thermostat or headgasket?

JOE DD

MEMBER
2004 DODGE NEON
4 CYL
FWD
AUTOMATIC
118,000 MILES

I have a 04 Dodge Neon. Drove it today to work, no problems until I pulled into work, heard what sounded like pressure releasing. Opened hood, found coolant leaking from the overflow reservoir vent, reservoir was now overfull. Let it sit for a few hours, came back to check it, let it run for awhile, all seemed ok, coolant fan came on after a bit but never cycled off. Let it run for a good while, never overheated or got past half way on the temp gauge. Seemed to take for ever for the top hose and top of radiator to get hot but the heater hoses were hot quickly. Decided to take it for a quick drive, temp gauge started to climb almost right away. Turned on the a/c and it went to hot and coolant was coming out of reservoir. My question is. Would this be just a thermostat or do I have headgasket issues. There is no intermix in the oil, no smoke from the tailpipe. The car has 118k miles on it.
Thanks in advance for any advise

9 Replies

CJ MEDEVAC

MECHANIC
11,004 POSTS

With you mentioning the upper radiator hose did not get hot (while over heating? Or just running normal temp?) Maybe the thermostat had not opened yet?

Then the fan running forever?

Kinda hard to say what to tackle 1st?

EZ 1st?

I'd check the fan relay next, it may be working only intermittently, I'd also check the coolant temp switch. Sounds like one or the other is possibly not telling the fan to work at proper times. The switch may not be sensing correctly, or maybe the relay's contacts are sticking.

A experienced parts feller or manager, at a popular parts store may be able to assist you with 1st hand identification of these, on your vehicle.

Your owners manual or fuse box lids might identify the relay.

If nothing happening up there, replace the thermostat next.

All of the above are sorta simple tasks to check or replace, even for a novice DIYer.A buddy with some experience might help you out too, even just for moral support!

Unless you let it overheat a lot, your head gasket and head may not be damaged. They can be pressure tested, if it comes down to getting that far.

Let me know if you may need further assistance, and how it all turns out!

The Medic

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Saturday, July 9th, 2011 AT 3:39 AM

SATURNTECH9

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The best thing to do is get a temp gun to make sure the thermostat is opening at the correct temp. You can also make sure the fan is coming on at the correct temp. Also if you have a air compressor I would blow out the a/c condensor and radiator fins. If they get fur sand etc that can cause overheating. You could have a bad thermostat with using a temp gun hard to say.

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Saturday, July 9th, 2011 AT 3:41 AM

JOE DD

MEMBER
14 POSTS

Thanks for responding. Let me clarify. Upper hose did get hot but seemed to take a long time, same with top of radiator, heater hoses were hot long b4 upper hose. Both fans run like they should with a/c on, regular fan came on after awhile (a/c was off) but never cycled off and ran continously.I didnt let it ever actually overheat, just when it got close to the H then I shut it off.
As long as I let it idle, it never got past halfway on the gauge but as soon as I took it for a ride, it steadily climbed to hot within a block or 2 of driving.
Is this a t-stat or am I looking at a headgasket?
Aslo, it has a reddish coolant. Is this that Hoat stuff. Doesnt appear to be oil in coolant.
Thanks

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Saturday, July 9th, 2011 AT 3:47 AM

SATURNTECH9

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Sounds like a thermostat but without seeing what the actual temp the thermostat opens at we could only guess if it was bad thermostat. If you want try replacing the thermostat you can but without gettng a temp gun and doing some actual diagnosing to see when the thermostat opens and what temp the comes on I cant tell you for sure whats going on. Even if I was there with your car I would have to do that to see whats going on.

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Saturday, July 9th, 2011 AT 4:27 AM

DANLESABRE

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230 POSTS

There also might be a combination of two different problems. The radiator may be clogged (and not circulating enough coolant) and the thermostat may not be functioning properly. Either and/or both of these conditions may cause the symptoms you are experiencing.

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Saturday, July 9th, 2011 AT 4:43 AM

JOE DD

MEMBER
14 POSTS

Thanks Medic, saturntech, DanL
I tossed in a t-stat while it was cold today, ran it, bled system. Took it for a ride, trans started neutralling out right away, checked and added a quart, after still showed a little low. Drove it again, neutralled out again alot, rechecked fluid, none on stick, added 2 more quarts, then drove it again, stopped to check, coolant was overfilling in reservoir, but it wasnt overheating and temp gauge read 1/2 way. Cooler in radiator must have ruptured. Going to replace it monday
Wouldve noticed it sooner if it had green coolant but with the red, it threw me off. Anyway, new radiator on monday, ill update you. Thanks again for the advise, really appreciate it.

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Sunday, July 10th, 2011 AT 2:50 AM

SATURNTECH9

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Your welcome glad to hear you found a bad radiator atleast your getting somewhere with this. Keep us posted.

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Sunday, July 10th, 2011 AT 2:59 AM

JOE DD

MEMBER
14 POSTS

Thanks to all. Just wanted to thank you all and update you.
Replaced the radiator, flushed system, flushed heater core, replaced t-stat again, it was a failsafe from autozone and it was stuck open, changed trans filter, flushed trans, used 16 quarts til it ran clean. Filled and bled system. Drives fine now. Lucked out with trans.
Did notice the lower engine torque strut is broken. Looks easy to do but I hear there is an alignment procedure that needs to be done. Found procedure online, will do it just want to know if there is anything I need to watch for or do special from your experiences?
Thanks again, Joe

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Monday, July 18th, 2011 AT 3:39 AM

SATURNTECH9