can you repair viscus fan couplings?

no

appasab kumbar from banglore
September 2008

Viscous fan couplings can wear and become sloppy, so that the fan wobbles and rattles as it spins (perhaps taking a bite out of the radiator?)
I have "repaired" a couple by removing the nut on the shaft nose, fitting a suitable washer, and then refitting the nut.
This locks up the unit and makes it run true, but is now a fixed drive, not as makers intended, but it stops the rattle! Ideally, you should replace the unit.

Mr. Toad
July 2008