amonson1984

I've owned a 97 Civic EX since 2006. When I first bought the car that summer, the air conditioning worked excellently. The next year, when I moved to Arizona, it slowly began to blow hot air. I took it to a Honda dealership where the system was tested and they told me that everything appeared to be working properly, it was recharged and injected with dye. Several months later it was blowing hot air.

I took it to a different Honda dealership (the first one closed down), where I was again told everything seemed to be working properly, but to be certain they needed to remove the dash to inspect the entire system (quoted a couple hundred dollars just to inspect!). I was a broke student at that point in time so I suffered for two years without AC.

I moved away from Arizona, so when I had the cash, I took the car to a new dealership in a different state, where I was told the system appeared to be working properly - components in good shape, up to pressure, no leaks, etc. It was recharged with freon and injected with the dye - as it was the first time a few years back. It worked again for 6 months, and mysteriously began blowing hot air with little warning.

I'm hesitant to return to a shop/dealership and pay for a diagnosis without an idea of what the issue might be in advance - my dad suggested having the compressor clutch checked out. If all of the components are working, the system holds pressure, and there are no (apparent) leaks, where should I begin? Is there a way I can diagnose the AC on my own? I don't plan to own the car much longer than the next year or two, so I'm hoping for a cheap fix.

Any advice would be greatly appreciated!

CFiannotti

If there were "no leaks" why were you in need of "recharging" so many times? Perhaps a very miniscule leak,allowed enough gas to escape,over the course of 1 year.You would not notice it after the hot season ended, but 12 monhs later, when you go to use the AC for the first time, you would experience those problems.

chromal

There is a pressure switch that will prevent that AC compressor clutch from engaging if the system is low on refrigerant. You can look at the front of the AC compressor pulley; if the front plant isn't spinning, the clutch is not engaged, if it is spinning, the clutch is engaged and transferring belt power into the compressor. When you turn on the AC, does the clutch engage? If not, one possibility is that the system charge is low.

I agree with the other poster, what you describe sounds like a slow leak, e.g.: when it has been serviced, they found the refrigerant charge to be low and topped it off, and from there, it seems to work well for a while before failing again, down the road.

If previous AC services have added a UV dye, you may be able to find the point of the leak. It's probably one of the refrigerant line unions (e.g.: O-ring) or possibly where hardline joins rubber line. It wouldn't be surprising if one of these would begin to fail on a 15+ year old vehicle. You may also see an oil residue at the point of this hypothetical leak, from PAG oil.

amonson1984

Thanks for the advice so far!

How long does the UV dye typically stay within a leaky system? I have always been told that if the AC begins to blow hot air within a few weeks to bring it back and they can pinpoint any leaks, but can they still do that after several months or even a year?

After the most recent recharge (with the dye injected) in April 2011, I brought it back a few weeks later even though the AC was still running strong, and the dealership told me everything still looked okay. It didn't start blowing hot air until September and it seemed rather sudden, but my memory is hazy.

I will use your method to see if the compressor clutch is working properly, or try to find a shop that will offer a free AC inspection and check out some of the possibly leak spots that you mentioned.

chromal

I'm not sure how long any leaked dye would remain visible under a UV light. I'd expect it could wash off or get covered in grime after half a year, but it depends... If the AC stopped working because the system pressure fell below the tripping point of the pressure switch, I'd expect it to ... well, stop working like a switch was thrown. (Because it was. ) Although pragmatically, the system would be less efficient as the refrigerant charge got lower and lower, though by September, I suppose the days were getting cooler and cooler, too...

Good luck

nealnanoHX

If the ac high and low pressure are good and the ac compression is coming on but you still have hot air check the blend door. It controls the hot and cold mix.