Rep Power: 0

05 civic with 89k miles here. Couple weeks ago started having AC issues, it would stop blowing cold air after 30 min or so of driving. Then temp gauge started coming up to the redline and falling and back up again. I determined that radiator cooling fan was not spinning and took it to the dealer to confirm. They said it was exactly that plus filter clogged up. I took the car back home and replaced the fan myself. At first I thought it solved the problem but no my temp gauge still gauge to the redline, especially in low speed/traffic driving. Next I guess I can try replacing the filter, but what filter were the dealer referring to? Not the cabin air filter? what filters are there in the cooling system that can be affecting it? Also when changing my fan I pulled out the coolant overflow tank and noticed that it was totally empty, but no apparent leaks. Am I having the dreaded head gasket issue??? The dealer also told me my AC system was fine....
Any suggestions???

 
Rep Power: 517

The AC system can be shut down by the engine computer when it sees an overheat condition.
So....Your AC system is probably ok but your engine is overheating.

You say your overflow tank was empty.
Did you open the radiator cap and check/refill the radiator?
Do that, burp the radiator, and refill the overflow bottle to the MAX line.
A low coolant level is just as bad as fans that don't work.

Then make sure both of the radiator fans work.
Did your shop just confirm a(?) fan didn't work, or did they diagnose it as a bad fan motor?
One or both? There are 2 fan motors, you replaced one of them?
Both are supposed to run at the same time.
Fuses checked and good?

Will both fans run with the AC on?
Will they both run when the coolant gets hot enough?

Search for the sticky on overheating.



"Filter"(s) might have meant the cabin filters for the HVAC system up behind the glovebox.

 
Rep Power: 0

Honda factory trained master tech.

Sounds like he fan switch sensor (located on the thermostat cover) is starting to go. Super common on this model. This could be the reason the a/c quits. The switch stops supplying the input to control the fans which disrupts signal to run the a/c. All the while your engine overheats.
I've replaced many a head gasket because of this part going out.
It cuts in and out when it fails. It doesn't just abruptly stop working.
Replace that fan switch I mentioned and cross your fingers about the head gasket. But if you overheated it you can expect to repair that sooner or later.
Good luck man. There are two cooling switch sensors. Make sure you get the one in the thermostat cover NOT the top of the water jacket housing.

 
Rep Power: 149

Do you mean PN: 37870-PLC-004?
I found it here: http://estore.honda.com/honda/parts/...-5mt&dl=206735
Under Engine, Water Pump - Sensor
#17

 
Rep Power: 149

Or #16 which is PN: 37760-P00-003?

 
Rep Power: 517

37760-P00-003 is the radiator fan thermoswitch.

 
Rep Power: 0

Ezone got it right.