IF the sound comes from inside cabin Scott is right on spot.
IF the sound comes from engine bay it could be:
1.as previously stated a bad AC compressor bearing.. in this case I would start by inspecting the ac clutch bearing-> this doesn't need to evacuated the refrigerant from system.
2. ac compressor bearing.
3. Idle pulley bearing
4. even tension pulley bearing
make sure all belts are in good condition and that all parts associated to the AC comp. are good too(tensioner pulley bearing, idler pulley).
gl
Airflow is required in the car as well as over the condenser out by the radiator.
without it you will "slug the compressor" with a liquid which springs your reed valves. The pressure on the high side will go to the max and it should shut off, if not it can burst.
Safeties in the system are supposed to shut it off so it cant try to work without airflow or air movement.
Have somebody look while you try it and see.
Get it checked before it gets too expensive.
It may have already been damaged.
air condisioning units in cars can be fragile and contain dangerous gases. i would personally get it looked at by a mechanic. but not just one. go to a few of them to be sure you are getting a good deal. it could be the compressor as it sounds like it could be that and would most likely be that as it is the most common cause of this. especially in cars
If it does not make the sound when your AC is not engaged then the bearings of your AC compressor have failed. The unit will have to be replaced.
Sounds like the blower fan bearing is shot, or the blower itself is faulty.
Sounds like the compressor is knackered - it won't fix itself: you'll have to have it repaired.
Sounds like a loose oscillation adjustment screw to me...
you should have it looked at by a mechanic.
When i turn my ac on in the car it makes a rattling noise. It also does not blow air out. When the a/c is off it does not make the noise. What could be the problem?
