What causes A/C compressor to whir and hum? Can I fix it?
03-27-2016, 11:43 PM
#1
What causes A/C compressor to whir and hum? Can I fix it? I have a 2009 G8 with 190k miles. The A/C compressor makes a whirring / humming sound when it is running. It's pretty loud... definitely not normal however the A/C still works. I already changed the idler pulley and the A/C compressor pulley bearing. The noise is unchanged.
Well a reman'd compressor is about $400. Ouch. A seal kit is about $20. But before I get into that... if there is something inside the compressor making that whirring sound, what is it? Is it something a seal kit will fix?
A couple other things...
1) Maybe an incorrectly charged A/C system? (Too much or too little freon)
2) A bad belt? Is there a way to test that without replacing?
Well a reman'd compressor is about $400. Ouch. A seal kit is about $20. But before I get into that... if there is something inside the compressor making that whirring sound, what is it? Is it something a seal kit will fix?
A couple other things...
1) Maybe an incorrectly charged A/C system? (Too much or too little freon)
2) A bad belt? Is there a way to test that without replacing?
03-28-2016, 03:03 PM
#2
if the "AC still works" then it should not be an incorrectly charged system. I've never heard noises happen, especially as you describe, from the amount of charge being off (within reason).
not as easy as the main serp belt, but if you get a wrench on the tensioner pulley for the ac compressor you can vary the belt tension and see if the noise changes. if it does then it might all be in the compressor pulley/clutch/bearing. if not then internal to the compressor. don't lose your arm if you try this.
other thing i would do is put a set of gauges on there and observe high/low pressure as the ac compressor starts. if you see erratic readings then compressor might be on way out.
not as easy as the main serp belt, but if you get a wrench on the tensioner pulley for the ac compressor you can vary the belt tension and see if the noise changes. if it does then it might all be in the compressor pulley/clutch/bearing. if not then internal to the compressor. don't lose your arm if you try this.
other thing i would do is put a set of gauges on there and observe high/low pressure as the ac compressor starts. if you see erratic readings then compressor might be on way out.