Still Chasing AC Problem - Now Going After An Unexpected Noise

[copsahl]

Have you tried listening for the whine up-front, near your passenger side ac condenser?

[thom4782]

Thanks for the suggestions so far.

The noise isn't radio related. It's there whether or not the radio is on.

I'll double whether it comes from one of the condensers. I might be surprised. The sound however seems like it coming from the area under the expansion value / pollen filter. I suppose it could be the evaporator.

Two follow-on questions if the sound is coming from the condenser or the evaporator, hyw would one of these components make a whining sound? Why would it change with engine speed? I could guess the answer to the second question -- the refrigerant pressure and flow rate increases as the compressor speed increases. If the noise is flow related, the its pitch could be higher with greater flow rates.

[Meir]

Thom. Try this.
If the evaporator is leaking, AC oil should be released along with the freon.
Put the AC on high, and activat the defroster (direct the air to the windshield )
After 5 minutes, use your finger and inspect he windshield for oily substance.
If it is not oily, at least you will know the evaporator is fine.
Did you charge the AC with a dye?

[thom4782]

Hi Meir:
The AC was charged late last summer with a dye. It showed a leaking expansion value. I replaced it as well as the receiver / dryer. Now, four months later, the AC isn't cooling so there must be another leak. I'll try the window trick to see if its the evaporator. Hopefully not.

I'm still wondering about the whining noise. It's been making before the system was recharged, when it was freshly recharged and now several months later with the refrigerant level low.

Thom

[newBgeek]

Hate to drudge up an old thread, but I'm also having this whining noise coming from the expansion valve. The A/C still works and blows cold air. Otherwise, same symptoms as the OP. Anyone else experience this and found a cause?