Cooling fan / viscous coupling

[JayB5UK]

Should the fan spin up all the time, i.e. from cold? I think mine does and sometimes the car makes a fan-like noise when accelerating. Kind of like a plastic bag being sucked towards the fan or something.

Wondered if it might be the fan being driven when not needed?

1.8T engine, it's done 112k now by the way.

Any help / experiences gratefully received.

 

[madvw]

one spins permanently, and the other comes on when you turn on the AC or when it overheats.

 

[FezzR]

the viscuous fan will run all the time, but it has two speeds.

when the coupling fails it will run in the fast speed all the time, leaving you with the Shogun sound effect as i like to call it where your engine sounds more like a huge fan than a power horse.

 

[JayB5UK]

LOL - Shogun noise, I know exactly what you mean! I'm glad to say it's not doing that, but it either sounds like a fan or possibly leaking boost, but a mate hooked his laptop up and we went for a run with the vag-com program running and there was no apparent boost leakage according to the requested boost and measured boost readings.

I am at a loss now. I used to think it was my standard diverter valve flapping about and changing it for the bailey did improve the sitaution a bit for a while but now it seems to be making the noise again under boost?!