ac compressor squealing after belt removal
 

i was tracking down a coolant leak this morning on my 3.0 and I had removed the belt to check the water pump. after I was done and reinstalled the belt, I got a very nasty sounding squeal/screech from the ac compressor. I know it's the compressor because when I turn the ac off the noise goes away. I don't know why it's making noise but I need some suggestions on what I could do to fix this

Check the adjusting pulley.

Loose belt, tighten the belt and it should go away.

If the belt is loose meaning the adjusting pulley is bad. So, you cannot tighten the belt manually.

like I was saying before I only hear the noise when the ac is on and this never happened before

You only hear it when the AC is on because the clutch turns freely when the AC is off and has resistance when the AC is on causing the loose belt to scream--tighten me.

ok so how can I tighten the belt

As I mentioned above, the tensioner (adjusting) pulley will do that for you if the thing works properly. You cannot do manually adjust or tighten the belt.

so these tensioners that comes on our cars are 1 time use? because this is the first time I loosened the belt since switching to a hydraulic tensioner

that's what I thought. I have maybe 20k miles on it so I doubt it has failed

FYI

https://www.youtube.com/watch?v=Tzx0kIKRD1g

Seeing that he has the M54 engine, this is a better video on replacing the belts.

https://www.youtube.com/watch?v=eWvwzN7VQl8

well I ended up taking off the belt and putting it back on and the noise went away :dunno:

Do you know why the noise went away? What did you do that was different than the first time?

I installed the belt "wrong" once (I think I had it on the wrong side of the idler or tensioner) on my N62

It would squeak a bit when I blipped the throttle. I think I ran it for about 25 miles before I figured out what was wrong. Oops.


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I have made many similar mistakes along the way. Like you I just say oopsie. When I stop learning I start dying.

mine was only squeaking above 2500 rpm with the ac on. luckily I only did about 4 miles before I fixed it

I must have installed the belt wrong. I just removed the entire belt, wiped it clean and installed it back