Jeep is overheating at idle

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Jonas Menges

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Apr 18, 2018
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Houston, TX 77082, USA
My jeep is overheating at idle which is a very unusal situation it just started yesterday and cant figure it out, i was looking at another post but some of my sympotms are different, my ac works just fine, it set on cool still blows cool air, and it being on hot still blows hot, so water has to be flowing. But it still overheats.
Any advice would be great, thank you
 
If your engine temp is high only at idle but normal at cruising speed, that's typically a symptom of a bad fan clutch.
If you can freely spin the radiator fan by hand, with engine off of course, that is a good indication the fan clutch is not turning enough at low rpm
If the fan clutch is ok, I would want to know the age and/Or history of the other cooling system components, and go from there
 
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Also, is the coolant low by chance? The thermostat could be sticking too, do you know when the thermostat was changed last?
 
X2 to the fan clutch suggestion. That's what would cause the engine to overheat only when stopped when no air is flowing through the radiator fins from driving. Low coolant or bad thermostat would cause overheating in all conditions, driving and stopped.
 
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Jonas Menges said:
My jeep is overheating at idle which is a very unusal situation it just started yesterday and cant figure it out, i was looking at another post but some of my sympotms are different, my ac works just fine, it set on cool still blows cool air, and it being on hot still blows hot, so water has to be flowing. But it still overheats.
Any advice would be great, thank you
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Im having this exact problem. Im changing my thermostat and flushing the coolant. Will try to give an update.
 
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Brandon Casey0 said:
I

Im having this exact problem. Im changing my thermostat and flushing the coolant. Will try to give an update.
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Before spending any money try this: Start the engine and let it idle until the temperature gets to ~ 210F. Shut the engine off and look at the fan to see if it’s “free-wheeling”. If it is, the fan clutch is bad.
 
IMHO, it's likely either the fan clutch or your radiator is low on coolant. For me, my radiator was really, really low! I felt like an idiot chasing the problem, only having it end up to be the simplest solution.
 
Brandon Casey0 said:
I

Im having this exact problem. Im changing my thermostat and flushing the coolant. Will try to give an update.
Click to expand...
As above, if it's overheating only when your engine is idling, it's very likely the fan clutch. A bad thermostat or bad coolant would cause overheating at idle, slow driving, fast driving... in other words, a bad thermostat or coolant would cause overheating in all driving conditions.
 
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Jerry Bransford said:
As above, if it's overheating only when your engine is idling, it's very likely the fan clutch. A bad thermostat or bad coolant would cause overheating at idle, slow driving, fast driving... in other words, a bad thermostat or coolant would cause overheating in all driving conditions.
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The first thing I did was test the fan and its working properly. So I'm not sure what else it would be
 
Brandon Casey0 said:
The first thing I did was test the fan and its working properly. So I'm not sure what else it would be
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I can't think of anything else that would cause it to overheat just during idle conditions. How did you test it? The fan clutch should let the fan freewheel only when cold but when the engine/fan clutch is hot, the fan clutch should make the fan very hard to turn.
 
Jerry Bransford said:
I can't think of anything else that would cause it to overheat just during idle conditions. How did you test it? The fan clutch should let the fan freewheel only when cold but when the engine/fan clutch is hot, the fan clutch should make the fan very hard to turn.
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I let it warm up and cut it off and checked to see if it was spinning and it wasn't, I also tried to move it by hand when it was cold and there was some resistance
 
Brandon Casey0 said:
I let it warm up and cut it off and checked to see if it was spinning and it wasn't, I also tried to move it by hand when it was cold and there was some resistance
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That isn't convincing evidence to me that the fan clutch is in good condition. That it doesn't continue to spin after the engine is stopped doesn't mean it's working properly. Also there should be little resistance when the clutch is cold.
 
Jerry Bransford said:
That isn't convincing evidence to me that the fan clutch is in good condition. That it doesn't continue to spin after the engine is stopped doesn't mean it's working properly. Also there should be little resistance when the clutch is cold.
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Well theres just enough resistance to keep it from spinning free when its cold. Its hard to explain with words
 
When I had the same symptoms a few years ago, I replaced the fan clutch. When doing the popular spin test, I could not tell the difference between the good and bad clutch. Regardless, the new clutch solved the overheating at idle problem.
 
jjvw said:
When I had the same symptoms a few years ago, I replaced the fan clutch. When doing the popular spin test, I could not tell the difference between the good and bad clutch. Regardless, the new clutch solved the overheating at idle problem.
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How many miles did you have when you had to replace it?
 
Maybe I've not seen it, but I can't recall anyone actually finding that the failed clutch was free spinning. Quite often, that method of diagnosis doesn't seem to work.
 
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