Overheating!!

[dwright318]

My engine is overheating at low speeds. It will run hot and cool down and it will run hot and cool back down like intermitting overheating and what I’m saying overheating it at 260° or higher but when it runs hot, I pull over and shut the engine off For safe measures. What may be the cause of this?

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[smokeythecat]

What engine do you have? My 3.6L runs consistently at about 225-230F, which I've always thought seemed high, but 260 definitely doesn't seem right. Again, I don't know what engine you have.

It's probably not a good idea to shut the engine off when it is overheating. I know it sounds unintuitive, but when you do that you stop the flow of coolant through the block and allow heat to build up. Pull over, but keep it running and watch the temp.

 

[dsgrey]

Could be the thermostat amongst other things such as radiator, water pump, fan, etc. I assume the fan is running, overflow tank shows coolant, etc? How many miles on your 2018? Thermostat would be the more obvious reason.

 

[dwright318]

What engine do you have? My 3.6L runs consistently at about 225-230F, which I've always thought seemed high, but 260 definitely doesn't seem right. Again, I don't know what engine you have.

It's probably not a good idea to shut the engine off when it is overheating. I know it sounds unintuitive, but when you do that you stop the flow of coolant through the block and allow heat to build up. Pull over, but keep it running and watch the temp.

I have a 3.6 manual and it will go all the way to the red line when hot and then it will come down in just a few seconds of being hot

Could be the thermostat amongst other things such as radiator, water pump, fan, etc. I assume the fan is running, overflow tank shows coolant, etc? How many miles on your 2018? Thermostat would be the more obvious reason.

That’s what I think as well as the 3.6 L The fan is running high, has coolant in the tank and no leaks, but I also have Replace the head due to a misfire

 

[dwright318]

I have a 3.6 manual and it will go all the way to the red line when hot and then it will come down in just a few seconds of being hot

That’s what I think as well as the 3.6 L The fan is running high, has coolant in the tank and no leaks, but I also have Replace the head due to a misfire

It has 121,000 miles on it

 

[rdfact]

I have a '21 3.6 auto. I have seen my coolant temp get to 253 when I was on a long climb up a mountain in early August, outside temps were about 100. I was coming back from camping and was loaded up with gear.

 

[roaniecowpony]

I have a 3.6 manual and it will go all the way to the red line when hot and then it will come down in just a few seconds of being hot

That’s what I think as well as the 3.6 L The fan is running high, has coolant in the tank and no leaks, but I also have Replace the head due to a misfire

The fan should be annoyingly loud, running at its highest speed. It should be constant until the temperature drops below the schedule threshold, which others can chime in on, but it would be something like 235F and above for "High". If the fan is going up and down, when coolant temperature is above the threshold, it could be indicative of a PCM problem. @alphawolff helped me with diagnosing my PCM. He may be able to give some further insight to what's going on with your jeep.

 

[58Willys]

Have you checked coolant level? Is your radiator clogged with mud? Pressure test cooling system for leaks? Fan running when hot? Have you checked for DTC‘s (codes)? Does it actually exhibit sings of overheating, or could it be a bad temp sensor?

 

[Phrank]

It's that grill and those 20s. Your Jeep is trying to self-immolate out of pure shame.

 

[alphawolff]

My guess is a failing coolant temperature sensor or a massive air pocket. If it got to 260f something is seriously wrong, and it definitely shouldn't just randomly start coming back down again. The fan should be running at 100% speed well before getting to that point.

 

[dwright318]

My guess is a failing coolant temperature sensor or a massive air pocket. If it got to 260f something is seriously wrong, and it definitely shouldn't just randomly start coming back down again. The fan should be running at 100% speed well before getting to that point.

What’s the best way to get rid of the air?

 

[alphawolff]

What’s the best way to get rid of the air?

Question: Why do you have air in the first place?

JL coolant bleed is just fill it till it's full and let it run for a bit.

 

[dwright318]

Question: Why do you have air in the first place?

JL coolant bleed is just fill it till it's full and let it run for a bit.

I had took the egr off so I could get the valve cover off I was having trouble getting it to come off. I replaced the intake cam phaser and oil control valve on the intake. And it didn’t fix my problem it was the intake cam on bank one all the lobes were wore down and then I still have a misfire code so now I’m replacing the head but the overheating just started happening. And I got it tore down for the head and I also noticed coolant leaking from the water pump. I’m just having all kind of issues at the moment I have 121800 miles on it but I know something about bound to happen to it.

 

[Old Dogger]

Running your engine at 260 degrees, possibly has already toasted your engine. I hope that I am wrong.

 

[RubiconJL392]

My engine is overheating at low speeds. It will run hot and cool down and it will run hot and cool back down like intermitting overheating and what I’m saying overheating it at 260° or higher but when it runs hot, I pull over and shut the engine off For safe measures. What may be the cause of this?

Get a temperature gun from Amazon or HF and check your hoses and radiator to see if the gauge temperature is reading accurately and to help you troubleshoot the issue.

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