Anyone ever have issue where ur Jeep overheats when running AC, never had this problem till we replaced motor with brand new crate motor. Already replaced New thermostat, new radiator, new radiator cap, systems been purged/burped several times. Dealership can't seem to figure it out.Been in and out shop for 7 weeks trying to figure it out. EDITED TODAY 9/13 Dealer has had it back for 3 weeks they have replaced clutch fan and water pump since my original post still over heating. At this point they don’t know what else to do. I’ve been dealing with this since July when they installed new crate motor.
Overheating when running A/C
- Thread starter Tracehow
- Start date
Look for debris in the condenser and radiator coils. I saw a friend tear his Camaro apart for an overheating issue. New everything including a motor. Finally he found the problem to be a radiator and AC condenser coil. Blowing them out from the inside with a car wash will clear the crap and allow everything to breathe again.
A bad fan clutch will also cause it.
A bad fan clutch will also cause it.
oldb
TJ Enthusiast
Never had a 4.0 apart, can you put the head gasket on upside down and block water passages? Or lord forbid if you really bore one out say .060 or beyond will they overheat due to thin cylinder walls? Mopar rebuilt engine or?
B
B
While we are all guessing at possible causes, and since you have already replaced all of the "usual suspects" for overheating and because your symptom is overheating only when the A/C is turned on, check to be sure that the A/C condenser is not clogged and that the A/C compressor is working properly. Although a faulty A/C compressor is not a common cause of overheating, it is a documented cause. If the A/C compressor is seized or otherwise not spinning properly it can prevent the serpentine belt from moving freely which in turn affects the cooling system.
I had this issue yesterday - i've never had the a/c on full blast before (usually 2 or 3 on the fan speed). It was like 90 degrees out, and drove the car for well over an hour in stop/go traffic and nothing was wrong. But then I got into a bit of a traffic jam where we were hardly moving for 15min, and I got hot not moving so pumped the fan speed up to max (4). Didn't realize it until the dash light came on, and the coolant temp was not maxed out, but just creeping into the red zone. I shut off the a/c immediately, and luckily 20 seconds later traffic opened up and I got to move (getting some air into the radiator) - and the temp regulated in less than 90 seconds.
The rad fan works, and everything else is fine. I've been in worse traffic with the a/c on before and never had an issue - the ONLY variable was that this time it was on the max fan speed instead of a middle speed one.
It seems that perhaps nothing is truly 'wrong' - other than the a/c on max in an essentially parked and idling car on a pretty hot day is a combination I should avoid. I think i'm going to check over the a/c clutch and condenser coils as mentioned above this weekend. I can easily avoid the max fan/bumper to bumper scenario in the future, but if it's a quick fix as mentioned I'd love to not have to worry again.
The rad fan works, and everything else is fine. I've been in worse traffic with the a/c on before and never had an issue - the ONLY variable was that this time it was on the max fan speed instead of a middle speed one.
It seems that perhaps nothing is truly 'wrong' - other than the a/c on max in an essentially parked and idling car on a pretty hot day is a combination I should avoid. I think i'm going to check over the a/c clutch and condenser coils as mentioned above this weekend. I can easily avoid the max fan/bumper to bumper scenario in the future, but if it's a quick fix as mentioned I'd love to not have to worry again.
Your cooling system has become marginal, it's ok until pushed on a hot day. That can be anything from the radiator becoming clogged with hard water deposits from having used hose (not distilled as should be) water in it to someone having installed a cheap store-brand radiator, a bad fan clutch, missing or damaged fan shroud, to the water pump going out... especially if the pump is starting to leak or make noise. Or have you ever wheeled in mud so your radiator cooling fins might be partially clogged with dried mud? Perhaps its coolant is simply old and in dire need of being flushed and changed. Even the thermostat may just not be opening fully and needs to be changed.
Do any of possibilities those ring a bell?
Do any of possibilities those ring a bell?
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None ring a bell - I just bought the thing a month ago and am slowly going through it as I learn and/or I have issues.
What I DO know:
Radiator is an OEM style, but seems very recently installed (looks brand new).
Thermostat was just replaced (by me) 2 weeks ago. That has been working perfectly after the swap.
Coolant hoses aren't brand new but didn't look bad at all when I had a couple open.
Seeing the few ounces that seeped out when I swapped the thermostat, the coolant didn't look too bad, but not sure of the water situation when refilled. Perhaps a full flush/replace on the coolant/water is in order.
I have to start looking at the shroud, the condenser, etc and a couple other things you mentioned as well. Learning a bit every day!
Thanks!
A newish radiator could mean the previous owner possibly went cheap on it. Seriously, most aftermarket radiators don't have any excess cooling capacity whatsoever which means it can overheat when conditions get even a little tougher than normal. If none of the easy suggestions help you may only be helped by replacing that radiator. If you do get to that point, do go with a Mopar (which has an all aluminum core) as it's about the only reasonably priced radiator that absolutely will keep the engine cool.
Mrblaine, a member here, builds Jeeps for a living and knows more about Jeeps than 99.99% of anyone involved with Jeeps. As such people occasionally bring him problems like an overheating Jeep that they have tried "everything" to fix on their own. His fix normally involves nothing more than replacing the aftermarket radiator the owner installed with the factory Mopar radiator.
Mrblaine, a member here, builds Jeeps for a living and knows more about Jeeps than 99.99% of anyone involved with Jeeps. As such people occasionally bring him problems like an overheating Jeep that they have tried "everything" to fix on their own. His fix normally involves nothing more than replacing the aftermarket radiator the owner installed with the factory Mopar radiator.
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