Air con strange noise.

[Druid1001]

Hi guys

I own a 2001 A4 (B5) 1.8 20v N/A

For a little while now i have been experiencing a strange noise when i put on the aircon. The noise does not occur when the heater blower is on economy mode.

As soon as you put it on air con mode the noise occurs. The noise sounds as if something is caught in the fan its almost like the noise of a squashed coke can in your bike spokes (for those of you who did that when they were kids).

It doesnt affect the actual air con itself. It still gets cold and works ok.

I mentioned it to my local garage and he thought it might need a new fan motor.

Im not sure how you would access the fan to check its not something silly like a leaf or small twig. Can anyone shed any light on the subject or point me in the right direction to take the fan out and inspect it?

Any help on the subject would be greatfully received.

Thanks Drew

[Druid1001]

anyone?

[green A8]

Hi guys


As soon as you put it on air con mode the noise occurs. The noise sounds as if something is caught in the fan its almost like the noise of a squashed coke can in your bike spokes (for those of you who did that when they were kids).

Im not sure how you would access the fan to check its not something silly like a leaf or small twig. Can anyone shed any light on the subject or point me in the right direction to take the fan out and inspect it?

Any help on the subject would be greatfully received.

Thanks Drew

To gain some access to the fan remove the pollen filter. You should be able to see the fan then, so if there is a twig or similar present you should be able to see it. Perhaps if you turn on the fan with the pollen filter removed that might help you to pin point the noise, and the cause of same.

If you want to go one step further remove the pollen filter than remove the plastic housing that it fits into (10mm nuts) I would suggest that you seal the bottom of the housing with silicone sealant to prevent water ingress on reassembly. Audi fit a sponge like gasket to the housing, which isn't very good at repelling water.

Hope this helps. Good luck.

Kind Regards.

Paul.

[kenney]

I think you got your fans mixed up,the fresh air blower(or heater blower)runs no matter if the AC is on or off,but the cooling fan for the AC only operates when the AC is switched on,You can inspect the fan from the engine compartment

[Druid1001]

Thanks for the replys

What am I looking for exactly? Is the ac cooling fan obvious when your looking under the bonnet?

I'll remove some of the plastic covers and have a look this eve.

Thanks drew

[kenney]

get someone to start the AC while you observe the engine bay and you will see the fan starting

[yaman]

Yes it could be the a/c cooling fan, and it could also be the
a/c compressor or fan-belt getting noisy under load.

Regards
Jim

[green A8]

I think you got your fans mixed up,the fresh air blower(or heater blower)runs no matter if the AC is on or off,but the cooling fan for the AC only operates when the AC is switched on,You can inspect the fan from the engine compartment

I think I have indeed got the wrong fan "Drew." Sorry about that. Thanks for pointing that out "Kenney" My Bad

I'm with "Kenney" on the idea of starting the engine and checking out any strange noises. It could be a number of things under the bonnet. as Jim points out, things may not cause a problem before they come under load. Correct me if I'm wrong chaps, but isn't there a seperate tensioner for the A/C drive belt? Perhaps that could be part of the problem?

A word of caution though "Drew" take extreme care when the engines running and dont get caught up in any of the moving parts. I know a very good mechanic who lost a large part of his shirt sleeve to a Bentley fanbelt! Thank God it was just his shirt sleeve.

Kind Regards.

Paul.