Viscous fan - do they wear out?

[PeteE30Tourer]

For the first time, i've really started noticing the noise my viscous fan makes. I am aware they're more noisy in the hot weather, but I just wondered if they wear out and become more noisy with age and hence if i need to replace it.

If so, are they easy to replace?

[TOURINGDADDY]

yep. best way to find out is to start her up and get her to opp temp then roll up a paper and try to stop the fan. if u stop it replace it if it shreds the paper then leave it

[stevo]

they sure do
cost me a head gasket the last time and this ones going the same way
what can cause blades to brake off the fan if its not even close to catching on anything, age?

[TOURINGDADDY]

by the way really easy to replace

[Brianmoooore]

By noisey, I presume you mean the noise from the fan itself.
That isn't a sign of imminant failure, that's a sign it's doing it's job in this hot weather.
Found out last week that the viscous unit on my 318 is due for replacement, as the temp gauge went into the red while in traffic in the hot weather.

[PeteE30Tourer]

By noisey, I presume you mean the noise from the fan itself.
That isn't a sign of imminant failure, that's a sign it's doing it's job in this hot weather.
Found out last week that the viscous unit on my 318 is due for replacement, as the temp gauge went into the red while in traffic in the hot weather.

I was led to believe the noise it makes is similar to a large articulated truck engine - a sort of low-pitched whine. It does seem that it's better now the weather has cooled down a bit. Temperature guage sits just over the half-way mark, which i gather is ok.

[M5pilot]

If its making that noise then its working.

In this weather they do come on alot more than normal because the radiator cannot disperse the same amount of heat into the hotter ait surrounding it - basically its not efficient enough in this weather.

I had a similar problem with my M5 and I fitted a new coupling and it still sounded like a lorry all the time. I found the radiator was too dirty.

Check how dirty the outside of the rad is. If you cant see through it take it out and run water through it. Beware of where you do it because it can make an almighty black mess!

Cleaning the outside of the rad is a practice everyone should do as to keep the radiator to its maximum effieciency. You should be able to see straight through it.

[koos]

had a prob with mine, sitting in traffic and the gauge kept rising, not good.when the gauge goes past the middle, give it a rev and you should here a whoosh sound. when cold air is going through the rad onto the coupling you dont hear a thing, but as soon as hot air blows on the the coupling it becomes solid and the more you rev it the more of a whoosh sound you here. read online that you can fit a electric fan, not bad, more reliable. genuine fan Ԛ£130, aftermarket one, same make as genuine Ԛ£35. Easy to fit, 32mm spanner, whack it with a hammer, left hand thread.

[Brianmoooore]

I can assure you that the standard viscous fan is more reliable than any electric fan, especially an aftermarket one, by several orders of magnitude.