Engine overheating

2003 JEEP GRAND CHEROKEE
200,000 MILES • 4.0L • 6 CYL • 4WD • AUTOMATIC
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PHILMARJ
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when car is moving temp is ok, when come to a stop the car starts to over heat
Mar 23, 2014 at 7:55 AM
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HMAC300
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check coolant level and have system pressure checked for a n internal leak. also make sure your electric fans are coming on. This guide can help us fix it.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down this guide and report back.
Mar 23, 2014 at 9:02 AM
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PHILARLO
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do not have elect fan
Mar 24, 2014 at 2:43 PM
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HMAC300
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then it may have a fan clutch so check that it should lock up when it gets hot. if you have one when engine gets hot it should be very hard to turn or not at all. if it does it's probably bad. also check for cold spots in radiator if you feel any the rad is bad. it shold be the same temp all across. Of course do this with the engine off.
Mar 24, 2014 at 3:10 PM
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JANICEG
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Engine overheats when running air conditioner. Does not happen when moving at speed but temperature will start to climb at idle. Does not happen at all in winter.
Dec 9, 2020 at 2:30 PM (Merged)
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HMAC300
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check to see if fans are on when a/c is on they should be. then check for a bad radiator, check for cold spots on rad when it's hot. if you feel any then you have a bad radiator.
Dec 9, 2020 at 2:30 PM (Merged)
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JERRYN75
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I have changed out the water pump and thermastat. the heater doesnt work never even gets warm just cold. I dont think the coolent is going through the motor at all????
Dec 9, 2020 at 2:30 PM (Merged)
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WRENCHTECH
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The reason you get no heat is because the core is filled with air instead of coolant. You may not have gotten all the air out when you filled it or you could have a blown head gasket. We use a vacuum fill tool to get all the air out.
Dec 9, 2020 at 2:30 PM (Merged)
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JERRYN75
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This started before i replaced the thermo and pump? someone else said possibly my heater core was bad, is that the core you were refering to? there does apper to be a leak , but its coming from my fire wall. if it was my head gasket, wouldnt be mixing with my oil???
Dec 9, 2020 at 2:30 PM (Merged)
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WRENCHTECH
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No, it wouldn't necessarily be mixing with oil. The most common type of head gasket failure is combustion gases getting into the cooling system which creates superheated air in pockets. Your heater core could be plugged but the only symptom would be lack of heat but not any overheating. You can try removing both heater hoses and flushing it in both directions with a garden hose under pressure.
Dec 9, 2020 at 2:30 PM (Merged)
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MINDOWN BUSINESS
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I have replaced the radiator, the water pump, and the thermostat and the jeep keeps overheating------WHY
Dec 9, 2020 at 2:30 PM (Merged)
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CARADIODOC
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Have you checked if the radiator fan is turning on? If it is, the next step is to have a chemical test performed at the radiator to check for a leaking cylinder head gasket.
Dec 9, 2020 at 2:30 PM (Merged)
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ANNETTE KENNEDY
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no that did not answer my question
Dec 9, 2020 at 2:30 PM (Merged)
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ANNETTE KENNEDY
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i replace the radiator, tstat, hoses and it still runs hot. help
Dec 9, 2020 at 2:30 PM (Merged)
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CARADIODOC
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You're kidding, right? You expect me to answer your question but you refuse to provide any information??? Did you even bother to read my reply?

This is like calling my doctor and telling him "I'm in pain". He has no clue if I have a hang nail, I cut my foot off with a chainsaw, or my ex-girlfriend came back! You can be sure I'm going to have to provide some details and answer some questions.

Now, if the radiator fan is not turning on, the engine will overheat at low speeds. It will not overheat at highway speeds because natural airflow is more than sufficient.

If the fan is running properly, the engine can still overheat if a cylinder head gasket is leaking. Combustion gases can get into the cooling system where they will pool under the thermostat and prevent it from opening. Thermostats have to be hit with hot liquid. They won't open in response to hot air. Replacing the thermostat won't solve that problem because it isn't the cause of that problem.

The inoperative fan and a leaking head gasket are the two most common causes of overheating. You replaced the parts that are least likely to cause overheating. Once you check the two things in my first reply, we will know how to proceed. Until then, anything is just a guess.
Dec 9, 2020 at 2:30 PM (Merged)
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MICHAEL ELLIOT
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I cant explain why but got a call from a friend yesterday asking if I could change a 02 sensor on a 2001 grand Cherokee v6 because it was over heating again.
Scratching my head I had to ask how came to conclusion the 02 sensor was the cause and was told this is the 3rd time over the last 5yrs or so that its happened and each time they replaced 02 sensor and fixed the problem!!
Hope this helps everybody and someone else can probly explain the correlation of why
I'l would assume causes engine to run too lean cuz a lean mix will burn thru top of a piston!!
Dec 9, 2020 at 2:30 PM (Merged)
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LYNN53
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Ive had it for 12 yrs and it drives fine but when i turn on the AC it overheats when im stopped for a light i have put in a larger fan and checked the water pump and checked the fan relay switch what else would it be
Dec 9, 2020 at 2:30 PM (Merged)
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CARADIODOC
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You don't need a fan that's larger than the original, but more importantly, how did you fit that in there? Is the shroud missing? If it is, that will let the hot air go back around repeatedly through the radiator and get hotter and hotter.

Most of these had electric fans, and since you found a related relay, I assume that's what you have. Obviously check that the fan is turning on. If the fan is dead, the engine will not run hot at highway speed.

The next thing is to look at the cooling fins on the radiator. If they're corroded and crumble easily when you rub them, that will reduce their effectiveness at giving up the heat to the surrounding air. The additional clue will be both radiator hoses are real hot.

If the cooling fins are in good shape and not blocked with debris, look for the rubber seal under the leading edge of the hood. That has to make a seal on the core support to prevent air from bypassing the radiator. There also can't be any holes in the core support, for the same reason.
Dec 9, 2020 at 2:30 PM (Merged)
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CARADIODOC
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Three times in five years? And an oxygen sensor caused it? I think it's because the driver ran over a pot hole while turning right and driving after dark. That also might only happen three times in five years.

Next time the engine overheats, I suggest someone actually diagnose the problem, or at least install some other random part that's easier to get to. Better yet, put one of the old oxygen sensors back in, then you'll see the engine doesn't overheat.
Dec 9, 2020 at 2:30 PM (Merged)
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LYNN53
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it runs good it just happens when the AC is on not when im running the jeep with out the ac on and the fan i put on is a jeep fan just a little stronger one so thats all good
Dec 9, 2020 at 2:30 PM (Merged)
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NOMI91
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I am having problems with my 2000 jeep grand cherokee laredo.
It shakes horribly like the steering wheel wants to go off by itself but most importantly i have had an issue with it heating up for the past 2 years.
Its leaked out the antifreeze ive had the radiator replaced and alot of the insides replaced as well.
With summer coming its starting to act up again as soon as i turn it on it just kind of shakesfor a few minutes then stops
also when i turn it off and ive had the ac on it sounds weird like a loud hurricane sound.
so far ive taken it to 3 different mechanics just this month alone
but now im worried because last yr i had it straight wired and now the electrical system is whats wrong but i told the mechanics i chose to get it straight wired because of the previous problems before.
so now im not sure what to do and if its possible to get it back to the way it was before without straight wiring and what kind of mechanic am i looking for or if i need a new motor as one mechanic told me.
Dec 9, 2020 at 2:31 PM (Merged)
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KHLOW2008
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That would depend on what is causing the overheating and coolant losses. If it is leakages depleting the coolant, rectifying the leakage should solve the problem but based on the symptom of shaking when engine is started, it is likely that you have a misfiring cylinder and that could be due to bad head gaskets.

Checking is not going to solve the problem. Get a pressure test done to confirm if it is the head gasket that ios bad.

It is always possible to get the wiring system back to standard but it would depemnd on what had been done and faulty compnents has to be replaced.
Dec 9, 2020 at 2:31 PM (Merged)
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DEHNER1
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Two months ago my wife was driving my Jeep home from work (it was during January - sub-zero temps) when it started to overheat - she didn't notice the temp gauge rising. She drove it until it completely shut down. Because of the cold, and not being able to get it into a mechanic it sat at our house until we could work on it. My son is a trained mechanic and we set about trying to determine if it was a workable situation. I had recently installed a new alternator and water pump just before this incident and since then we have put in a new radiator (the old one was cracked), serpentine belt , and belt tensioner. A complete oil change was done as well. We have purged the cooling system as best we can but there still seems to be a lot of air in the system. The heater core seems clear but I am not getting any heat in the cabin. Today as I tried to go to work it overheated again (after we thought we had it fixed) and I watched as coolant gushed out the overflow tube on the coolant reservoir. Please respond with any suggestions! I love this Jeep and would rather not get rid of it!
Dec 9, 2020 at 2:31 PM (Merged)
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JACOBANDNICKOLAS
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Have you replaced the thermostat? Have you tried bleeding the heater core?
Dec 9, 2020 at 2:31 PM (Merged)
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DEHNER1
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Thanks for the reply but I got my answer today. My son brought out a test kit to check for a warped head (by checking for exhaust gases in the coolant). Got a positive result. :( I guess the next step is removing the head and having it milled (if possible) and replacing it with new gaskets and bolts.
Dec 9, 2020 at 2:31 PM (Merged)
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JACOBANDNICKOLAS
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A bad head gasket will do it.
Dec 9, 2020 at 2:31 PM (Merged)
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MARRA1986
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This morning my 1994 Grand Cherokee cut off at the light it started shaking and hissing and smoking from the grill. The temperature went past the red. What could have caused it to run hot. I checked all fluids everything was filed. The car had been sitting for about 10 months prior to me driving it today.
Thank you for your help
Dec 9, 2020 at 2:31 PM (Merged)
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JACOBANDNICKOLAS
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Are you certain that the coolant is full? How long were you sitting? Did the cooling fan turn on?
Dec 9, 2020 at 2:31 PM (Merged)
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MARRA1986
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Yeah It had some in there and When I parked it the fan never came on! I was at the light for about 5mins at the most.
Dec 9, 2020 at 2:31 PM (Merged)
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JACOBANDNICKOLAS
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If there coolant in it and the fan didn't come on, my guess is that is what caused it to overheat. When you sit still, there is no air flow through the radiator like when moving. Thus, the cooling fan should come on.
Dec 9, 2020 at 2:31 PM (Merged)
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LADYKATIE
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99 jeep grand cherokee laredo, my car was overheating and the fan wasn't coming on. i had a new radiator and fan put in about 2 months ago. its overheating again and has no heat.

Overheating had radiator replaced and fan as well coolant needs to be filled constantly but have found no leaks when it starts to run hot, i turn the heater on...now my heater is blowing cold air. also the radio has been cutting out.
Dec 9, 2020 at 2:32 PM (Merged)
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ASEMASTER6371
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sounds like the coolant is low again. you need a shop that will insert a dye into the system to determine the leak. if none is found, which I doubt, they need to do a leak down test to see if you have a blown head gasket and you are burning it.

Roy
Dec 9, 2020 at 2:32 PM (Merged)