Hi all, I'm trying to diagnose my wife's car and hoping you can help. I saw a thread similar to mine but due to the fact that mine is inconsistent rather than not working completely I thought it may be a different issue.

So, here goes:
The a/c blows strong and usually it's hot air. I've found that if I get the car to 4K rpms and hear a short hissing noise (like an air connection getting sealed, sounds like it's coming from behind the vents in middle of dash) the a/c will start blowing cold in a few seconds. When it's cold, its very cold; however, the cool air will last for any where from 10 to 45 minutes. If I stop, it almost always gets hot again.

I took it to a mechanic and he told me everything seemed fine and that he couldn't replicate my issue - that I would have to bring it back when the ac wouldn't blow cold.

[Edit: I should note that the 4K rpms 'trick' doesnt always work, that's just the only thing I've been able to do with any success]

I would appreciate any suggestions that a diy'er could check on to try and fix the issue.

Thanks much!

Chris

 

ONLY WHEN THE A/C IS ON BUT WON'T BLOW COLD, do this:

1) Check whether the condenser fan runs.

2) Check whether the compressor clutch engages.

Post the results.

 

Thanks for the reply RonJ...I wasn't sure how to check either of those so a colleague recommended I take it to one of his friends...He just called back and said the clutch on the compressor is bad and that it was trying to engage and the noise I heard was it actually catching but it wouldn't last long.

Thanks again!

 

Usually you can take the shim washers out of the clutch, bringing the plate closer to the pulley to compensate for wear and make it engage reliably again. It could last quite a while longer.

 

Thanks mk378...I talked to the guy and he quoted $460 to replace the compressor; he told me that I couldn't replace just the clutch. I can't spend $460 on the car right now, I'll let my wife drive my car and I can deal with the heat.

Is what you are suggesting, or replacing the entire compressor something a diy'er could handle on my own? The most complicated thing I've done on a car is replace an alternator (old VW) and replace a thermostat (same civic in question). Would I need special equipment to handle the freon?

Thanks!

 

This is a fairly basic zero dollar DIY job. To adjust the clutch you can leave the system charged. Get under the car and take the splash shield off. Unscrew (conventional right hand threads) the nut on the compressor shaft. You will need to hold the clutch plate from turning somehow. There is a special tool for that but it could work to just hold a screwdriver across the rivets. Be careful not to mangle the flat springs on the plate. With the nut off, the plate will slide off and you can find the shim washers on the shaft and remove some or all of them then put the plate back on. Note that the splines are designed so the plate will only slide onto the shaft in one "clock" position. Try to get the plate within .020 inches of the pulley. Closer is OK as long as it doesn't drag when off.