I recently purchased a 1999 Nissan Sentra with 189K on it. The car runs great and the AC ran ice cold. The porblem was when the AC turns on a very loud noise is heard it sounds like a million crickets chirping.
I took it to a mechanic and he said it was a bad AC Compressor. So I replaced the AC compressor, belt tensioner pulley and serpentine belt.
The noise is still there.
So here is my further troubleshooting:
- the noise is clearly present when the AC is on.
- With the AC off the noise is heard only in short burst of maybe a second or two.
- When I remove the FAN relays (all 3) the noise goes away (with or without AC on).
- If i leave the fan relays in a disconnect the FANS power, you can still hear the noise. (So the fans are not the issue)
- I also removed the AC clutch and the noise is still heard.