Viscous Fan Coupling

N

Neil Beauchamp

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Location
Burwash, East Sussex UK
Hello All,

I think my viscous fan is about to pack up ( working intermittently and temp often too hot or too cold ).

Any suggestions where to go for a replacement? I'd like to keep it original.

Many Thanks,

Neil
 
do you really have a viscous clutch, or is that the original friction fan coupling ?

if it is the original friction, i can solve your problem, or at least i guess i can, i solved mine
 
Last edited:
So deQuincey,

Did you figure out a way to repair the style of fan clutch shown in your photo on this page?
I have one and parts are NLA.
Was thinking of just locking it on?

Gary
 
m5bb said:
So deQuincey,

Did you figure out a way to repair the style of fan clutch shown in your photo on this page?
I have one and parts are NLA.
Was thinking of just locking it on?

Gary
Click to expand...

well gary, basically there are two critical parts in the assembly,
the piston, and the friction spyder (shown in my photo)

if the piston is NOK, try to find a new one, or a better one, good luck, as they are difficult to repair

if the piston is OK (more likely) and the friction spyder is not working because the friction pads had been worn out (thickness of friction pads had become too thin to contact the metal when piston pushes it against the metal wall), then my experience has been to get the friction pads replaced by a specialist shop

whether you can get a replacement or rebuild the spyder, that is the way to go to recover a full working fan

i wont lock it on, but,...

i assume that you might get it sorted out locally, anyway if you can not find an easier solution you can send it to me and i will be happy to get it replaced with new friction pads for you, it will take time for sure,...
 
These original friction style clutches are a blown head gasket/cracked head waiting to happen. I had mine locked on (like the manual says to do in an emergncy), when I upgraded to the 9 blade fan and viscous clutch not only does it cool better but it is quieter and more reliable.

m5bb said:
So deQuincey,

Did you figure out a way to repair the style of fan clutch shown in your photo on this page?
I have one and parts are NLA.
Was thinking of just locking it on?

Gary
Click to expand...
 
Stevehose said:
These original friction style clutches are a blown head gasket/cracked head waiting to happen. I had mine locked on (like the manual says to do in an emergncy), when I upgraded to the 9 blade fan and viscous clutch not only does it cool better but it is quieter and more reliable.
Click to expand...

hi Steve,

normally i do not attempt a discussion with you, we usually coincide in almost all aspects, but i am surprised to read that the 9 blade is quieter and more reliable

i am not trying to convince anyone but to convince myself about this

it is a usual fact that viscous clutchs fail, unpredictably, mine did so, as a result an erratic behaviour of the temperatura, it is right, though that it does not fail catastrophycally

as to noise i can not recall it being louder, but,...maybe i do not remember well

regards
 
deQuincey said:
well gary, basically there are two critical parts in the assembly,
the piston, and the friction spyder (shown in my photo)

if the piston is NOK, try to find a new one, or a better one, good luck, as they are difficult to repair

if the piston is OK (more likely) and the friction spyder is not working because the friction pads had been worn out (thickness of friction pads had become too thin to contact the metal when piston pushes it against the metal wall), then my experience has been to get the friction pads replaced by a specialist shop

whether you can get a replacement or rebuild the spyder, that is the way to go to recover a full working fan

i wont lock it on, but,...

i assume that you might get it sorted out locally, anyway if you can not find an easier solution you can send it to me and i will be happy to get it replaced with new friction pads for you, it will take time for sure,...
Click to expand...

Thanks deQuincey this is in a friends 74 all original coupe and I'm trying to keep it that way.

I think the friction material is worn down but I really don't know what to look for when it comes to the piston. I just got it apart this afternoon.

I think the new fan and viscous coupling is a great way to go and have it on my M5 and 533i. Just won't keep that stock look.

Can you tell me a little more about the piston?

Thanks,
Gary
 
I don't think anyone here has empirical evidence of reliability but I agree with Steve. BMW switched to the viscous fan for a reason. The friction fans did not last very long, although I realize there can be exceptions, and the viscous clutch and nine blade fans pull more air through the radiator and I think mine is quieter as well. Yes, viscous clutches can fail as well. Does any car manufacturer still make a friction clutch fan? It is old technology IMHO.
 
Compared to locking the 5 blade to always on it is quieter i believe.

Gary i have a practically new friction clutch i can send you.

Easy to test the viscous clutch. And i throw a backup in the trunk for long trips.
 
Stevehose said:
Compared to locking the 5 blade to always on it is quieter i believe.

Gary i have a practically new friction clutch i can send you.

Easy to test the viscous clutch. And i throw a backup in the trunk for long trips.
Click to expand...

Wow Steve,
you think it works?
I would love to have it.
Be glad to give you a Fed Ex number for shipping.

This car gets driven very little but will start to overheat when in traffic.
I can set it up so electric AC fan comes on all the time which I may have to do.
 
Yes I bought it right before converting to 9 blade. Yikes if it overheats in traffic why take the risk of blowing the head? It's easily reversible, unless he is doing a full on concours soon. The 5 blade is also more turbulent i guess because of it's offset blade pattern, it would cause fuel to drip into the #1 barrel of my webers.


m5bb said:
Wow Steve,
you think it works?
I would love to have it.
Be glad to give you a Fed Ex number for shipping.

This car gets driven very little but will start to overheat when in traffic.
I can set it up so electric AC fan comes on all the time which I may have to do.
Click to expand...
 
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