Weak AC on idle, but gets back to normal when car is running

**poorprince** · May 7th, 2014 10:46 PM

That's exactly my recent concern. Car is cool again when running, but no coolness when in idle mode (like AC is 50% off and FAN only). Do i need to replace parts, clean system etc? thank you very much tsikot experts

**_Cathy_** · May 7th, 2014 11:02 PM

I had the same problem with my Corolla. It loses cold air when the car is running slow or idling.

The AC shop replaced the Aux fan and it fixed the problem.

**alfonsomiguel** · May 8th, 2014 01:52 AM

Originally Posted by poorprince

That's exactly my recent concern. Car is cool again when running, but no coolness when in idle mode (like AC is 50% off and FAN only). Do i need to replace parts, clean system etc? thank you very much tsikot experts

Sa case ng Honda City 03 namin, ok naman yung fan at may freon naman. Palit ng expansion valve. Backgound: Bagong linis sya at bagong filter-dryer. After 1 month naging hilaw na, cool when running but no cool when idle. Buti pede dukotin expansion valve na dina ibababa ang evaporator..

**poorprince** · May 8th, 2014 02:03 AM

thank you sir and mam! my car is a Civic 99 EK. will check the aux fan, but the prob with Civic EKs is the aux fan doesnt automatically spin when you turn on the AC, you'll have to wait for a few minutes when it reaches a certain temperature for it to engage. anyways will check, otherwise might be an expansion valve as mentioned.

**non-vtec** · May 8th, 2014 06:40 PM

Originally Posted by poorprince

thank you sir and mam! my car is a Civic 99 EK. will check the aux fan, but the prob with Civic EKs is the aux fan doesnt automatically spin when you turn on the AC, you'll have to wait for a few minutes when it reaches a certain temperature for it to engage. anyways will check, otherwise might be an expansion valve as mentioned.

That's weird. Aux fan should turn on when the compressor is on. You might have a problem with the wirings. It could have been tampered or modified before.

**poorprince** · May 8th, 2014 09:50 PM

Originally Posted by non-vtec

That's weird. Aux fan should turn on when the compressor is on. You might have a problem with the wirings. It could have been tampered or modified before.

yes, the aux fan turns on when the compressor engages, when it disengages or i think what they call "trip-off" (clicking sound), the aux fan goes off. Aux Fan Spins again when Compressor re-engages. Same thing with the radiator fan, only spins when reaching a desired temp, then turns off, to save energy perhaps? is my setup ok? thanks!

**colt** · May 9th, 2014 07:48 PM

I have the same problem. I had the following parts replaced: filter drier, condenser, evaporator to laminated, expansion valve. A/C cleaning done and flushed. Pressure reading on compressor is normal. Radiator fan is working fine. I also added a 3rd aux fan in front of the condenser.

Kindly advise po kung ano sa tingin ninyo ang pwede pang gawin.

BTW, when car is running at least 30KPH a/c temp can go down up 2-3 degrees C. But when car is idle, it can hardly reach 10-12 degrees C.

I am using a pen type thermoter to monitor the air coming out of the center a/c vent

**funkeemunkee** · May 10th, 2014 11:47 AM

Originally Posted by poorprince

yes, the aux fan turns on when the compressor engages, when it disengages or i think what they call "trip-off" (clicking sound), the aux fan goes off. Aux Fan Spins again when Compressor re-engages. Same thing with the radiator fan, only spins when reaching a desired temp, then turns off, to save energy perhaps? is my setup ok? thanks!

Ideally, dapat sabay na mag-actuate ang condenser at rad fan when you turn on your aircon. Maybe that's why bitin ang lamig pag idle. You can have the electricals hacked para magsabay na yung dalawang fan. Mas buo lamig pag ganun kesa dun sa rad fan na nag-actuate lang pag init na ang makina. Pa-check mo na lang entire AC system para wala nang tsambahan sa diagnosis.

**non-vtec** · May 13th, 2014 07:22 PM

Originally Posted by poorprince

yes, the aux fan turns on when the compressor engages, when it disengages or i think what they call "trip-off" (clicking sound), the aux fan goes off. Aux Fan Spins again when Compressor re-engages. Same thing with the radiator fan, only spins when reaching a desired temp, then turns off, to save energy perhaps? is my setup ok? thanks!

Not sure with the Civic's fan setup. But the aux fan is triggered by the compressor, while the rad fan is by the temp sending unit. Or both fans should turn on when the water temp is high. So I think its normal.

First thing you should do is to visit a legit aircon shop. Get the readings from the high side and low side. If you are experiencing high pressure, even when the aux fan is on, it may need replacement na. If not, then maybe your compressor is no longer efficient. When you rev the engine, does the aircon get colder?

**dr. d** · May 8th, 2014 07:00 PM

Originally Posted by poorprince

That's exactly my recent concern. Car is cool again when running, but no coolness when in idle mode (like AC is 50% off and FAN only). Do i need to replace parts, clean system etc? thank you very much tsikot experts

i had the same problem with my non-corolla/non-honda car. it seems, i had a leak and had no freon. the "cool" i experienced when running at speed, was simply the effect of compressed air expanding.. everything went back to normal when i had the leak remedied and the freon refilled.
and i agree.. the aux fan should turn on when the compressor is powered.
perhaps the prince is confusing over the aircon's aux fan and the car's radiator fan. perhaps someone tampered with the original wiring.