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AC causes overheating when not moving.

7K views 13 replies 7 participants last post by  Galf 
#1 ·
We got our 2001 Kia Sportage a little over a year ago. The AC made it overheat from the beginning. This summer has come on fast and strong, so we are trying to fix it (plus we are expecting a baby in the next few weeks and really need it working). We found the AC condenser fan was not spinning, so we replaced that, and the new fan spins great. We did a coolant flush and filled it up with 50/50 mix. Helped a little. The problem is, when we are stuck in traffic, the AC goes warm and the car starts to overheat. If we turn the AC off, the car cools back down to normal operating temperature right away. If we're driving at least 30-40 mph, it doesn't overheat and the AC stays blowing cool air. The car never overheats when the AC is not on...even sitting in traffic.

Any thoughts on what we should try next?

Oh, we do need to replace our valve cover gasket, could that be causing this problem? We don't see oil except on one spark plug when we take it out l, and we were told it's leaking onto the plug when we unscrew it...not while it's in and running.

Thanks :)
 
#2 ·
It sounds like the fans in front and behind the radiator aren't coming on, .... need to check the fans, the temperature switch, and relay.


The oil from the valve cover gasket is not related, but if the oil still runs into the spark plug recesses, the gasket should be replaced.
 
#3 ·
We already replaced the front fan and it works. Kicks on as soon as we turn the AC on. Radiator fan keeps the car cool no problem when the AC isn't on. I don't know anything about temperature switch...and I guess I assumed the relay is good since the fan comes on.
 
#6 ·
If it was the radiator fan, wouldn't it overheat even when the AC is off?

Please don't think I'm arguing, I'm really just curious :)

I don't know a ton about cars...just a little...and it's pretty generic stuff. I really thought replacing the condenser fan would fix it...
 
#13 · (Edited)
If it was the radiator fan, wouldn't it overheat even when the AC is off?

Please don't think I'm arguing, I'm really just curious :)
The air conditioner increases the engine heating, indeed if the engine overheats the engine control unit automatically shuts off the air conditioner.

That saved my Sportage one time, because I noticed that the engine was overheating when I noticed that the air conditioner was not working any more; I almost never look at the engine temperature gauge. Of course that was caused by the radiator fan clutch.
 
#10 ·
Its worth the $$ to upgrade to the electric fan. You can test the fluid clutch to see if it is working properly. Family friend had a similar problem and a fresh recharge on the freon fixed her prob( was dumping more hot air in front of the radiator). Dont think kia uses freon thought it might have been oil of some kind but might wanna look into getting it charged.
 
#12 · (Edited)
Its worth the $$ to upgrade to the electric fan. You can test the fluid clutch to see if it is working properly. Family friend had a similar problem and a fresh recharge on the freon fixed her prob( was dumping more hot air in front of the radiator). Dont think kia uses freon thought it might have been oil of some kind but might wanna look into getting it charged.
Your comment just reminded me that this vehicle has the viscous fan coupling, which of course gets problematic with age, and would now agree with @Galf.
You need to replace the radiator fan, it wears out after some years, about every five years.


It would also be my preference to upgrade to the electric fan.
 
#11 ·
I don't know about in the US, but in Australia it is way cheaper to simply replace the fan and viscous clutch as an assembly than to do an electric fan conversion. Mine cost $60.00 Aud and took about 1 hour to fit, my first fan clutch lasted about 9 years.
I advise replacing as an assembly because as the plastic fans age the blades get brittle and cracked, whack an old fan onto a new clutch and the sudden increase in load may cause a blade to snap off and sail right through your radiator.
 
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