...since we're on the subject of Passats, in the last week I noticed a rumbling noise from the engine bay. Further investigation shows that it is the smaller one of the two fans at the front of the engine bay. Sounds like something is trapped in the housing but I can't actually find anything. The noise went away for a while then, when I was driving slowly along I turned the aircon on and the noise started again. I've tried it several times since, turning the aircon on and off and it is definitely linked.

So, what do we reckon? Shagged fan bearing? If so, any recommendations for sources of a replacement fan? The car is due a service soon but I'm guessing the garage will want a premium for getting the part and then fitting it.

btw the aircon still works fine

Oh, it's a 99 Passat 1.8 20v SE Estate, if that makes any difference.

Cheers

Simon

Don't know the layout on the engine your talking about but I presume the fan your talking about is and electric cooling fan.

The AirCon compressor is linked to the drivebelt pulley via an electro magnetic clutch. I suspect that it's related to the bearings / internals of the AC compressor when it spools up. The system does have an oil preload to lubricate the compressor - not sure if you can do an oil change / add oil or not.

On my A6 there is a viscous fan than makes a lot of noise (air movement noise though) up to 3k rpm and then decouples.

It used to work correctly and was quiet during the winter but noisy in Summer but not anymore.

In re

My AC compressor clutch went, I'd have thought more likely that than the fan bearing..... You could just unplug that 2nd fan and see if the noise goes away with the AC on - if not, it's the compressor...