Viscous Fans

[Danno]

Anyone considered removing the viscous fan and replacing it with a kenlowe or similar electric fan?

I thought viscous fans sap precious BHP from the engine ( I could be wrong! )

May gain a little more mpg too

Discus................



Dan.

[kitesurf_phil]

There has been loads of discussion on the viscous fans. It's worth doing a search. From what I can gather (as a former spannerphobe) is that the fan is supposed to slip on the viscous clutch, when the engine is cold and as the engine warms up the clutch engages to turn it. When they are old the oil viscosity changes and they don't work as well.

I don't know what the trade off is, by going to an elecric fan or if the electric fan will put more load on the alternator and cause the engine to work harder. Its all about energy efficiency. I have often wondered why they dont run the air con compressor with an electric motor, thus taking the load off the engine.

I,m sure someone will pop up and put their two-penn'orth in.

[wibblywobbly]

I always thought that they worked on the basis that when the radiator was cold then they spin freely, and when the radiator was hot they 'engaged' thus turning the fan and cooling the engine (eg when stationery). I thought that this disengaged at speed when enough air was coming through the radiator to cool it using airflow alone, thus reducing the BHP soak.

I seem to recall that the way to test them is to try and spin them with the engine cold, and then with it hot. The secret is in the word 'viscous', as that indicates that when the fan reaches a certain temperature that the internal clutch operates.

Mind you. mine is the same either way, so I am shafted aren't I!

There is an Aussie site where someone explains how to replace the goo in the viscous clutch somewhere. Does anyone have the link?

Cheers

Rob G

[Pete]

I always thought that they worked on the basis that when the radiator was cold then they spin freely, and when the radiator was hot they 'engaged' thus turning the fan and cooling the engine (eg when stationery). I thought that this disengaged at speed when enough air was coming through the radiator to cool it using airflow alone, thus reducing the BHP soak.

I seem to recall that the way to test them is to try and spin them with the engine cold, and then with it hot. The secret is in the word 'viscous', as that indicates that when the fan reaches a certain temperature that the internal clutch operates.

Mind you. mine is the same either way, so I am shafted aren't I!

There is an Aussie site where someone explains how to replace the goo in the viscous clutch somewhere. Does anyone have the link?

Cheers

Rob G

http://slowspeed.com/repair/fanclutch.html

It's for a Land Cruiser, but the repair is the same.
Pete

[Elvz]

An electric fan seems to have a lot of advantages over a viscous fan for a vehicle manufacturer like cost, quieter operation, and more and neater mounting choices, but strangely you don't see many on new diesel vehicles.

New vans which are pretty much state of the art with intercoolers, twin cams, 4 valves a cylinder, and common rail injection still have very ordinary viscous fans just like a Surf.

I think manufacturers like Mercedes and Toyota still don't consider electric fans to be reliable in the long term.

[bensonsnuts]

An electric fan seems to have a lot of advantages over a viscous fan for a vehicle manufacturer like cost, quieter operation, and more and neater mounting choices, but strangely you don't see many on new diesel vehicles.

New vans which are pretty much state of the art with intercoolers, twin cams, 4 valves a cylinder, and common rail injection still have very ordinary viscous fans just like a Surf.

I think manufacturers like Mercedes and Toyota still don't consider electric fans to be reliable in the long term.

Just had this reply back from Pacet

I Asked......

Hi,
I am interested in changing the viscous fan on my 1990 2.4td Toyota HiluxSurf (manual) for an electric model.
I use the car mainly on road where I need a fan that is going to cut in automatically, but I also use it on off-road days regularly where it can be in water up to half way up the radiator. At times like these I would like to be able to isolate the fan via a switch in the cabin.
The present fan is approx 42cm diameter & when removed would leave a gap of about 10 cm btween the rad & the engine.
I forgot to mention I also use the car to tow my caravan.
Can you tell me if any of your products are suitable ? I tried your website...but it keeps " hanging " my computer.
Do you have any stockists in the NE of England ( M,bro)
Price etc ...any info appreciated

Reply reads
Hello,

The TCF1611P (£147.61), i.e. one of our 16" puller kits (aprpox 406mm ) has a 95mm deep motor and therefore should fit easily enough. We also have a 'submergable' motor for an extra £15, a switch to override th thermostat , part no CF470 costs $9.04, carriage is £8. You could buy from us direct or from Demon Tweeks or Europa Cars.
Regards