2.4 overheats when A/C is on

Jeep G

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Oct 24, 2020
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Honolulu HI
Just got my jeep about 6 months ago, and ever since I got it it would overheat in idle when the A/C is on, when the A/C is off it will still overheat but only after strenuous drives on hot days. I just replaced my water pump and thermostat and the problem still happens, I've flushed. my radiator twice as well and that seems to make it take a little longer to overheat than it would before but after a few days, it is the same as before. when it is about to overheat it starts to have a rough idle and the revs will drop every 10-15 seconds this part does not happen when the A/C is off. My uncle who I work on the car with thinks I need a new fan or fan clutch but I think a new radiator might be what I need, I am aware that I should buy only Mopar parts for longevity but I had trouble finding the OEM fan on the internet, any help would be greatly appreciated
 
I don't know much about the 2.4s. Do they have two fans? A regular fan and an auxiliary fan that comes on when the A/C is on?
 
Mine has only one fan, it seems to move a decent amount of air when I put my hand in the grille. I also should probably note that I have a 2006 model with the manual transmission and 76k miles and the "ice cold A/C" was the main selling point of the person I bought it from (My uncle who has been helping me fix it up), but he only ran the ac when the car was parked and inside a garage without ever driving it at all.
 
I have a 2004 with the 2.4, I thought only the 4.0 came with A/C, I have a hard enough time getting it to 65mph as it is.
 
Based on the known symptoms, If forced to guess I would guess fan clutch.

However, before taking anything apart I would also check the radiator cap for pressure and be sure there are no leaks anywhere in the cooling system (including heater core*).



___________________
*On my jeep, the symptoms described lead to discovery of a bad heater core rather than bad fan clutch - loss of pressure in the system due to the leak was the cause of the temperature fluctuations.
 
Based on the known symptoms, If forced to guess I would guess fan clutch.

However, before taking anything apart I would also check the radiator cap for pressure and be sure there are no leaks anywhere in the cooling system (including heater core*).



___________________
*On my jeep, the symptoms described lead to discovery of a bad heater core rather than bad fan clutch - loss of pressure in the system due to the leak was the cause of the temperature fluctuations.
The 2.4's are factory electric fans so we need to find out if his operates as the ac is switched on.
 
sounds like the radiator is a good idea, if you do radiator might as well change hoses at the same time. Mopar radiator system parts do seem hard to find, I did mine last winter and found all the parts at Rock Auto, they had the best prices and availability.
 
when I was doing my coolant system rebuild i did stumble across an article about the fan schrouds having a big effect on the 4cy. As someone mentioned above that should be evaluated.
 
SO, to answer jims question my fan is pretty much always engaged when the jeep is at operating temp, however, after seeing Jerrys comment I went and checked my shroud and the thing had gaps everywhere, I decided to try and use some e tape to seal the gaps just to see if that was the problem, I sealed it up then took her for a rip and got her really hot, up to at least 215 just from revving while at stoplights and having no air on, then I parked it and put the A/C on to as cold as it gets and it came down to below 210. we will see in the next few days if this is the real fix to the issue and if it is i am gonna have to come up with something more permanent than electrical tape, there is a fan shroud kit on extreme terrain.com but it is Mishimoto and I'm not sure it will fit my 2.4 or be as reliable as my stock one. I will keep you guys updated if i come up with a better fix or find out that the shroud is not the issue after all.
 
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What does the gauge read when climbing the Pali hwy?
If it get hot into the red then you might need a new radiator.

Call K. Ifuku @ 845-3877 and see what they recommend for a re-core.
 
Gauge never goes up while I'm moving, though the Pali is definitely strenuous on the 4 cyl, 3rd gear all the way:ROFLMAO:
 
SO, to answer jims question my fan is pretty much always engaged when the jeep is at operating temp, however, after seeing Jerrys comment I went and checked my shroud and the thing had gaps everywhere, I decided to try and use some e tape to seal the gaps just to see if that was the problem, I sealed it up then took her for a rip and got her really hot, up to at least 215 just from revving while at stoplights and having no air on, then I parked it and put the A/C on to as cold as it gets and it came down to below 210. we will see in the next few days if this is the real fix to the issue and if it is i am gonna have to come up with something more permanent than electrical tape, there is a fan shroud kit on extreme terrain.com but it is Mishimoto and I'm not sure it will fit my 2.4 or be as reliable as my stock one. I will keep you guys updated if i come up with a better fix or find out that the shroud is not the issue after all.
The fan shroud intact is absolutely necessary for correct operation, I would look at eBay or Davey's Jeeps for a used one. Meanwhile some decent Gorilla tape or similar should be a good temp choice.