I really stumped about my A/C ..NEED HELP !

[Jag42]

I have a 2006 Honda Civic coupe manual transmission with 97k on it. My A/C will not blow cold air when at idle or stopped at a stop sign,Traffic light,etc. It will blow ice cold air once the car goes about 2k rpm's or higher and continues to work great. As soon as you come up on a light and you shift in to neutral and coast the RPM's drop like a rock and the car tries to die and has a hard time to keep idle and blows warm/cool air but not cold. I know the compressor cycles on and off to save fuel and i understand that and i notice it only at speeds over 50 mph. I have also tried down shifting instead of coasting and it does no good. The Ac coolant has been checked 3 times and is full and has no leaks. I'm thinking it might be a 02 sensor,A/C pressure switch,idle needs to be adjusted,alternator? I also have friends with Honda's and the same car and year model and their car's a/c works just great. I have a brand new battery and a good alternator. I took it to one A/C shop and they said it was the compressor which is B.S.

[DrCoke]

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[Andrew21]

Does sound like the compressor. Its the only thing that drives the freon to circulate throughout the system.

O2 sensor.. Don't think so. That controls emissions.
AC Pressure switch. Possibly. Try changing it out. Its a cheap part..I think
Idle? Don't mess with that. If the car starts up fine and doesn't stall without the a/c, I wouldn't touch the idle.
Alternator? Nope, that only charges your battery and keeps your car's electrical system running.

Try the AC switch. Then the compressor

[languy99]

if it was a bad compressor it will show in the pressure gauges that a shop can hook up to the system, also remember that most ac systems are made to work above a certain RPM at full efficiency. Now at idle you will not get as cold air as when moving but no cold air at idle will mean a compressor problem but it could also be other parts such as expansion tube, low or too high pressures in the system and others. Take it to a very good AC shop and they can tell you exactly what the problem is, if it is a compressor they will also have to flush the system, change the orifice tube and the dryer. I have also seen blend door problems sometimes.

[DrCoke]

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[dr_King]

Impossible 2 fix your problem without me being there but lets start from the beginning. Most mobile a/c problems stem from a LEAK and then snowball from there. And you know its properly charged how ? All R134a mobile a/c systems are charged by WEIGHT not by pressure because pressure changes with temp and other variables. You must be charged according to the underhood sticker + or _ 1 oz of refrigerant and the correct amount of PAG oil. Now if the system is right, a guage set will show you high side pressure at outside ambient x 2.2 ~2.5 Ex. 100F outside your high side should be about 250. Low will between 25 ~35. Excessive high side means an obstruction and or contamination by atmosphere (air / moisture). NOTE THAT IF YOU CHARGED WITH ONE OF THOSE MIRACLE-IN-A-CAN REFRIGERANT SEALANT THINGS, YOU HAVE DAMAGED THE SYSTEM. That is a disaster waiting to
happen. Your compressor works (for now). Hook up guages and check high side pressure. If its high, spray cold water on the CONDENSOR and see if pressure decreases rapidly. If so, you might have a condensor issue / trash in the system and require somebody thats knows what their doing to flush & fix it. Running it till then will screw up the compressor. Remember a/c does NOT produce cold but rather removes heat. The result is cold. The refrigerant has to move in order for it to work. Heat is dumped from the condensor. Make sure the fan runs and its clean. Good luck.

[Hunter]

Looks like there is a very small leak in the system.This is more pronounced when the car is on idle.

[Sector_15504]

I notice the same thing on my 06 civic. Its much colder when driving vs idle. Interesting.

[johndoesix]

Idle up switch? Does the car idle properly with the AC turned off? The idle up switch raises the rpms around 200-300 rpms, to compensate for the added drag of the compressor when it engages. With the mileage on the car, you also need to have all the vacuum lines checked. Cracks or breaks in those lines will cause idle problems. Also suggest you peruse several of the civic forums. A model specific forum will usually have somebody that had the exact same problem and usually a fix.

[Hahns5.2]

Air flowing over the heat exchanger while moving will make the AC colder, however anytime the AC is on the electric fan should be on too.