Lately my a/c compressor is not remaining active when idling in very hot weather, such as sitting at a stoplight. Unless the car is moving, it will kick on then abruptly shut off repeatedly, resulting in warm air blowing in the cabin. Only when I get the car moving again does the compressor stay on and cold air resumes. When the compressor keeps cutting turning on and then shutting off it really drops the idle rpm's and doesn't make a very pleasant noise.

The compressor and high pressure switch are relatively new, both replaced less than 30k miles ago. The system does have a very tiny leak under the dash which requires me to top off the refrigerant every year or so by using a can of pure refrigerant and a gauge. I just had the dealership check the system a couple weeks ago to make sure it was cooling effectively and they confirmed it cooled to 38 degrees and there were no bubbles visible in the sight glass. Unfortunately the compressor problem has started to occur after the dealer looked at the car, so I wasn't able to have them look into it. Any ideas what could be causing this issue?

 

Sure sounds like the compressor is continuously cycling due to low freon

 

If that's the case I'll get another can of refrigerant and hook the gauge up and see what kind of pressure it has. Might be time to top it up. Is there any way to check the level of oil in the system?

 

Do a search online for these babies - a/c oil analyzers... you should be able to find these in 2 pks
http://www.redtek.com/win_oilanalyzer.html

 

Speaking of servicing the AC, I wonder if it is worth having the system re-energized even if there is not a leak to bring both the refrigerant levels back up and have new oil put in? Or should I leave well enough alone... Probably answered my own question... lol

 

If there's no leak then you shouldn't need to "bring the refrigerant levels back up"