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Golf IV 1.6 Air-Con noise - arnold2
My Golf IV 1.6 air-con works ok, but in the last couple of days of high heat, switching it on has had 2 effects - a reasonable loss of power on the engine, coupled with a sort of 'knocking' sound. Gets louder as you rev the engine more.

When I open the bonnet at idle, I can see the engine sort of 'vibrating' more than usual - turn the air-con off, all back to normal.

Any ideas ?
Golf IV 1.6 Air-Con noise - George Porge
Have a look at the drive pulley and belt with the engine running (keep your fingers out of the way!) my bearing have play in them and the pulley wobbles a little. Maybe your is the same or worse?
2 Dirty VW diesels and a Honda with an 18 inch blade
Golf IV 1.6 Air-Con noise - arnold2
yes, what i thought, the drive belt - does it run at the front of the engine ?

Value my car