Air Con diagnosis


I when I put on the AC - or in fact the blower fan too - I get massive belt squeal.

I think I can hear a bearing rumbling and I think therefore that it might be the bearing on the AC compressor pulley.

What's the best way to go about figuring it out for sure.

Do I just replace the clutch assy on the A/C compressor? or replace the whole compressor unit? Or just tighen the belt and see what happens?

Trying to figure out exactly what is up.... is it that the AC unit is good and the belt has gone?... or the clutch bearing has gone but the compressor is OK?.... or is the whole unit needing to be changed? etc..

I presume I could take the whole unit off and buy the belt for the non A/C version but I would prefer to get the A/C working if I could.....

By the way the AC does not blow cold but probs has not got any coolant in it anyway...

Any tips very much appreciated.

Hi it's a 1.2 16v 2004 car. Not sure of the horse power.

Thanks for the vid - yes lookd pretty simple to change the belt.

Maybe I am over complicating it thinking it is the bearing or the clutch.

Perhaps I will just change the belt and see what happens.
So for anyone who is interested I will post my progress.

Problem was belt squeal. A lot. I was heavily pushed towards the pulley on the AC compressor becuase the belt squeal came on when the AC was engaged.

I thought that it might nout just be the belt but might be bearing on the pulley or clutch problem as I thought I coudl hear grinding.

Anyway I thought lets start at the start....

I took the old belt off. It was very loose compared to the 10kg 4mm deflection spec and also it was quoite worn out.

Once it was off I found I could spin the puley by hand with no resistance and I found that I could turn the clutch no problem by hand but with some small resistance since I am actually turning the compressor itself. Both as they should have been.

So put on a new belt on. I made it fit the 4mm deflection with a 10kg weight between pulleys at the bottom on the longest run.

The squeal completely went away immediately.


When I eganged the air con and presumably the clutch was engaged the belt was now forcing the compressor to turn. There was a bang. I thought the new belt had snapped but in fact what I think happened is that the new belt was forcing the AC compressor to turn and whatever problem was going on inside it finally let go.... (previously the belt slipped now the belt 'won')

Now the compressor pulley frewheels all the time and the clutch does not engage.

I do not know if the problem was in the clutch or in the compressor itself. Nothing lost since the AC was already not working and I would have had to replace the clutch and or compressor anyway.

I do not know whether I will be bothered to sort the AC out or not. Looks like a tricky job to get that compressor out - presumably you need to access it from the bottom to get it out but also the top to connect the freon lines.....

Anyway that is there I am with it.