Once the car has been on a drive and is at running temperature if I turn the engine off whilst still warm the viscous fan can still easily be moved/ turned, I've been told this isn't right and it should be stiff to try turn with a warm engine, is this right? if so do I just get a new viscous fan to fix this? I've also been recommended to get an electric fan but I've done some searching and there seams to be mixed opinions about these, I just wondered what you guys would recommend as im new to all this and you all have the knowledge and experience on these machines.

 

Also to be a pain, mine has some idling problems (not hunting) to describe it I would say it idles right on tick over at about 1000 rpm but then out of no where it will drop to 500ish and sound like its about to cut out then sort its self out and go back to where it should be. any ideas thanks :)

In my opinion, it id ok that the fan free spins straight after a drive. The reason being is that the thermal mechanism at the front of the viscous coupling along with the radiator has had ample air flow due to forward movement. It is only when the car is stationary that the fan comes into it's own as the engine temperature will start to rise and activate the coupling.

This helps prevent the engine using power to spin the fan when it is not needed, thus not wasting BHP

When at idle, (after a few minutes) you should hear a definite roar of air being drawn through the shroud when you raise the RPM (very noticeable)

A simple yet somewhat risky way of testing is, from cold at idle with a very heavily gloved hand, you should be able to stop the fan from spinning by adding drag.

Once fully warm though, the fan should offer much more resistance.

You will be able to hear it though, when mine cuts in after a minute or so at idle, I can hear it from inside the car!

^^^What he said mate......

 

......And a brand new viscous unit is actually quite expensive if you try to get one now!!!

 

As for going electric, I have heard mixed opinions too - with these cars you do not want to compromise on cooling; so IMO a good, working, viscous unit will shift more air to keep thinks cool than an electric one. I'm no expert though - but if you do update to an electric unit, be sure to get one which can shift at least as much air!

 

IIRC Mike at MJP can supply a suitable unit.....

 

Richard:cool:

I purchased a used replacement viscous from Jeff @ zedworld for around £30 iirc. Mine was noisy straight from startup (crazy noisy!) some I assumed the coupling/clutch had locked or become unreliable.

Thanks for the replies! I got home from work and started my car up from cold and let it sit there for around 10/15 mins but got no "roar" from the fan the engine did warm up but the fan sounded the same the whole time, so am i right in guessing that there is something wrong with it ?

My fan "roars" as soon as I start it up.

 

"Roars" is indeed the only suitable word for it!!

Thanks for the replies! I got home from work and started my car up from cold and let it sit there for around 10/15 mins but got no "roar" from the fan the engine did warm up but the fan sounded the same the whole time, so am i right in guessing that there is something wrong with it ?

 

Do not condemn the fan coupling straight away, it is well worth spraying DW40 in the centre so as to lubricate not only the coiled spring but also the small central shaft that operates the internal valve/gate. They have a tendency to become stuck. It may mean you have to take the upper shroud off to access it but well worth the trouble.

 

Mondo, sounds like yours is permanently engaged. Not a bad thing with regards to engine temperature, just may struggle warming up sufficiently.

Maybe worth trying some WD40 also.

 

If when you add WD40, you may need to rotate the central shaft slightly just to make sure there is free movement. If so, please be very careful as the vane that controls the flow of viscous fluid is very fragile.

Do not condemn the fan coupling straight away, it is well worth spraying DW40 in the centre so as to lubricate not only the coiled spring but also the small central shaft that operates the internal valve/gate. They have a tendency to become stuck. It may mean you have to take the upper shroud off to access it but well worth the trouble.

 

okay thanks I shall try that tomorrow.