Has anyone experienced overheating when running AC?

Joined
Jan 15, 2020
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New Smyrna Beach, FL
I recently got a 2000 Jeep, 2.5L with 150k miles and it runs great... Except when I turn on the AC. When I turn it on cool, it works ok-ish, but it overheats the engine.

Also, I turned on the heater at full strength for the first time a couple weeks ago, and my headlights started turning on and off. It freaked me out since it was night time. Thankfully, I was still in my neighborhood when it happened.

I’m not very savvy with mechanical things, but I’m trying to learn. Any ideas as to what the problem might be? What should I look at first?
 
It's not normal to overheat when running the A/C if your cooling system and radiator are all in good shape. It could be nothing more than the previous owner installed an aftermarket radiator, few cool as well as the Mopar does, a bad water pump, or the radiator is clogged with hard water deposits from running regular (non-distilled) water in the system.
 
It's not normal to overheat when running the A/C if your cooling system and radiator are all in good shape. It could be nothing more than the previous owner installed an aftermarket radiator, few cool as well as the Mopar does, a bad water pump, or the radiator is clogged with hard water deposits from running regular (non-distilled) water in the system.
Gotcha, so I should check the cooling system, not the AC.
I had a new radiator and the hoses put in at a shop a couple weeks ago, and it still has the same problem as before—it only overheats when I use the AC. So I wonder if they were cheap and put in a poor quality radiator (I should have just done it myself). Is there a way of checking that without redoing the cooling system first?

Thanks for the response, by the way! I really appreciate it!
 
Well the first thing I would do is check the coolant level in the radiator when the vehicle has been sitting and is cold. See where that's at. You can also look on the radiator to see if you see any factory Mopar stampings. My guess is they used a shitty aftermarket radiator, which isn't advisable. However, even with an aftermarket replacement radiator, it still shouldn't be overheating when using the A/C.
 
Also, what do you think the problem could be that would cause the heater to flicker/ turn off the lights? Could it be a problem with the alternator? I have used my winch and lights but haven’t had any other issues with power like that.
 
Well the first thing I would do is check the coolant level in the radiator when the vehicle has been sitting and is cold. See where that's at. You can also look on the radiator to see if you see any factory Mopar stampings. My guess is they used a shitty aftermarket radiator, which isn't advisable. However, even with an aftermarket replacement radiator, it still shouldn't be overheating when using the A/C.
I check the coolant and other fluids weekly. Haven't noticed an issue yet, though the reservoir is just slightly overfilled, but not by much. I'll definitely check and see if I can find mopar stampings tomorrow.
 
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Does it overheat while driving, idling or both? If it is just at idle (and slow speeds) then it might be the fan clutch (after making sure there is enough coolant and what not)
 
I check the coolant and other fluids weekly. Haven't noticed an issue yet, though the reservoir is just slightly overfilled, but not by much. I'll definitely check and see if I can find mopar stampings tomorrow.

there should be a mopar logo on the bottom tank, to the driver side of the drain, facing the rear.