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Another problem: Overheating

17K views 15 replies 9 participants last post by  lekmedm 
#1 ·
We were going to a wrestling event tonight with my son and had to park in a public parking garage. The temp. gauge was normal until we turnrd into the garage and had to wait for cars. The temp. went almost to the red and the heat stopped working. It was only blowing cold air so I found a parking spot as fast as I could and shut the motor off. On the way home the temp. gauge had to get to the normal spot and stay there for 10 min. befoire hot air started coming from the vents. It returned to normal as soon as we started down the road. It has plenty of fluid in it but I think it could possibly be a weak thermostat. Can anyone help with this problem?
 
#2 ·
Sounds for sure like your coolant wasn't circulating through the system. I think the thermostat should be checked to see if it is opening. If you find yourself in a pinch like that in the future, you can always remove your thermostat completely just to get you home without overheating your engine.
 
#3 ·
If you find yourself in a pinch like that in the future, you can always remove your thermostat completely just to get you home without overheating your engine.
Is it easy to do that?
 
#6 ·
Does anyone know if the stock thermostat (52028898AE) is a "fail safe" type.

I had a probem with one of my Trackers this summer and the thermostat failed ... but it was the type that failed in the full open position, I assumed it was the stock thermostat at the time .. but now I'm thinking it was a replacement?

I know they are available for just about every car now ... but was curious if anyone knew if the Jeeps come STOCk with the fail safe model?
 
#9 ·
Believe it or not, all thermostats are designed to fail open instead of closed. But the fact of the matter is that they can still fail in the closed position. So then they came up with thermostats that have a mechanism inside that is supposed to open them if the coolant on the engine side is at "overheating" temperature. These thermostats are marketed as "fail open" thermostats and they seem to work fairly well, but they have been known to fail closed too. I've seen it a few times in the last year or so...

In my opinion, the best bet is to just replace your thermostat as regular maintenance. But make sure to buy a quality thermostat and avoid the cheap ones. And if you can find one that is said to fail open, that's a plus too.
 
#10 ·
unless you absolutely have to, let it cool a couple hours before starting on it. IF you managed to get the cap off while it was hot, the force of the gushing boiling water would seriously injure you....for life.

If it is running hot, the radiator has probably already boiler over at some point. probably would not need to dump fluid.

Replace it with a stock thermostat unless you live in an area where it needs to run hotter and top off the fuild.

On the other side, if you have not replaced you fluid for a while, now is a good time.

If the thing is still under warranty, dont bother. go to the dealer, go to lunch,come back, tada! it's fixed!! wish it was that easy....
 
#11 ·
Well I just got a dreaded answer to the problem that I have. See I also have been getting a cylinder 5 misfire code and the problem is more than likely a leaking head gasket. My dad has been a mechanic for 40 years and said that it sounds exactally like the compression being pushed back through the head gasket and pushing the coolant back in the reserve tank. That more than likely caused an air bubble and made the heat inside stop working. So now I'll have to call the jeep stealer and see what that repair will cost. This is pissing me off, less than 50,000 miles and just under 4 months owning it and this crap happens. makes me think less and less of chrysler products.
 
#12 · (Edited)
If you can run the vehicle for a couple of minutes with the cap off(cold start),
a leaking head gasket will blow coolant out of fill hole at radiator immediatly.
I would be surprised if this is the case and I would wonder about its past usage, but.....
You said the coolant is being pushed into overflow, right?
Is it returning to radiator overnite(cooldown)?
If coolant is not being blown out of radiator at cold start, but is pushing coolant into overflow, and not going back into radiator at cooldown, the radiator cap has failed on the suction side.
If I'm right, what happens is, with coolant full, cap on, and at ambient tempurature, start engine and allow to warm fully. As the coolant expands and pressurizes it lifts the lower seal on the rad cap and is admitted to the overflow. Once the vehicle is shut off, the coolant in the block and radiator contracts and causes a vacuum within the radiator. This vacuum pulls the coolant out of the overflow and back to radiator to keep system full.
If the seal ring, the larger of the two immediatly under the radiator cap is damaged in any way, or the one way valve below the spring on the radiator cap is compromised, the vacuum will not pull the coolant back into the radiator.
If you top off the radiator, the next time you check it will be low again and the overflow bottle level will rise higher and higher.
Seems too simple, but I have followed up many a tech who overlooked this simple failure.
Please do not interpet my attempt at diagnosing as disagreeing with your dad.
I am only trying to provide additional food for thought, one mechanic to another if you will.

Rob
 
#13 ·
I completely see where you're going with that explanation. I haven't tried that but I will try. The only reason he had his reason is that when cold if you accelerate hard when the engine is cold it will buck a little like it's missing then the engine light will flash and stay on. I've had a misfire on cylinder 5 code for about a month now and that's probably the reason. Also the reserve tank is low but not in the radiator. He told me to plug the #5 plug in the morning and check to see if it has coolant or has been discolored by the coolant and also pull the O2 sensor to check for discoloration on it also. If so that could be why I had the slow response code the other week along with the misfire. I''l know more in the morning.
 
#15 ·
I pulled the plugs yesterday morning and found no deposits or evidence that the head gasket was leaking. There was no coolant in the reserve tank so I topped it off and ran it a little while with no overheating. I did however find out my problem with the )2 sensor. About 3 inches up the wiring harness on the engine side the wires were laying against the engine and had burnt the insulation off and the wires were stuck together. After several hours of fishing wires out of the harness I spliced everything together and it now runs so much smoother. My average mile per gallon actually went up after this. I was told to take the #5 plug out in the morning and spin the engine over and see if coolant comes out of the cylinder and that should definetly tell the tale of a bad head gasket. Will report more as I find out. By the way thanks to all the help you guys have given me through this mess, I really appreciate it.
 
#16 ·
I had a Subaru with an internal head gasket leak. It blew coolant out the reserve bottle as well as through the cylinder. In fact, when it got really bad, there was a cloud of vapor coming out of the tailpipe.

In your original post I thought you said the coolant level didn't drop. Usually, coolant is best checked in the reserve bottle when the engine is at operating temp. If you are losing coolant, it will leave a closed system in only one of 2 ways: it will leak out so you will have a puddle of it under your truck overnight, or you're blowing it out through the cylinders. That second version has 2 potential causes as well. If you're "lucky", it's a head gasket. If you're not, it's a cracked cylinder head. I had this happen in my first car, a Mazda 626GT Turbo.

I hate to say it, but in any scenario, the loss of coolant sucks big time! :(
 
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