When I turn on my A/C, particularly when the outside temperature exceeds 75F, the A/C radiator fan on my 2001 VW Passat 1.8T acts like the fan is imbalanced such that it oscillates towards the front and back of the car as it spins, and this motion creates a clicking/grinding sound that stops almost immediately upon turning off the A/C (when the fan stops spinning). It seems to only do this when the outside temperature gets too hot. Any ideas?

For the moment unplug that fan!!!! Now with a heavy glove or stick or tool grab that fan and rock it back and forward and spin it. Don't trust these things not to turn on as even with you key out it could screw up and come on.

Now if there's anything wrong by feel get rid of that fan before it totally self-destructs and takes out the condenser, radiator and who knows what?

I bet the motor has gone bad but you should be able to tell. If this is also cooling the radiator you need this NOW. Motor may come separately or an assy. They aren't cheap but either is the damage it could do and you'd still need to fix the fan.

Watch out for the nut that holds the fan on the motor. Many are reverse threaded so don't get too aggressive with it if there's any question as they can handily snap right off. That will cause hair loss, marital problems and use of language we don't allow here!

I can't be sure what the trouble is but that sure sounds like it.

Good luck with the fix and if it's way too nasty expensive check out used. I know some on some other cars are up to like $650 -- hope not,

T
Tom Greenleaf - MetroWest Boston - USA
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http://www.autoacsystems.com/tomgreenleaf/

The only question I have about your advice is this: why does the fan work properly when the temperature is below 75F? I had trouble with the fan yesterday when it was hotter out, but I checked it again this morning to find it working fine. Could that be because of different speeds or something?

It may have two speeds. If it does and uses the same fan it still has to be checked that the motor and its bearings are ok,

T
Tom Greenleaf - MetroWest Boston - USA
_________________________________________

http://www.autoacsystems.com/tomgreenleaf/