Thread: discard the viscous fan on V8

I can tell you only my own experience with the Td5 which doesnt have such "explosion" in it like a petrol one and it was bad... the electric fan ( kenlowe type 17" one) didnt cool enough starting from +30*C outside temp which i think is not unusual down under, coolant temp went above 110 in no time with fan constantly running... i had to remove the whole setup(cos i had an addapted "tunnel" to it also to improve air flow) and put back the viscous fan... so IMO unless you get hold of an electric fan with the same "guts" like the viscous one maybe but i presume it willl have a too big motor to fit in there and also too big electric drain... think about that

if your V8 is having cooling problems then something is amiss. If in good nick then these engines in factory trim cope quite well with our searing summer heat.

May I suggest that the problem be identified - here I would be looking suspiciously at the radiator with a view to having it removed and rodded. Flushing only does nothing. Chuck a new water pump on whilst the radiator is out too and then replace the original viscous fan after putting a new hub in it.

Your cooling issues should then disappear.

Good luck!

An electric fan needs an alternator to drive it, there are losses involved whilst operating. A viscous draws little power when free wheeling and once locked up with the heat actually does its job without a fuss. I doubt if you'd notice any real improvement in economy going with electric fans. On my 4 cylinder 2.2 litre Merc the viscous is dying after 340 000km so I wired the monster electric a/c condenser fan to a manual switch. It draws 20 amps and you can feel the engine revs drop as it sucks power from the alternator. It does take the temp down though with the help of the weak engine fan. To cool a 4.0 V8 you'd need an even bigger electric fan motor, way bigger than a Davies Craig thingy.

I took off the mechanical fan and put electric fans on it. Had nothing but trouble. In traffic it was constantly overheating. Was fine on the open road but it was fine on the open road without a fan anyway.

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I was thinking this through once again awhile ago and evolved a theory that once you get going over about 60Kmh the airflow through the radiator drives the fan anyway, so you would have little drag on the engine.

When this thread topic has come up in the past about 1 million times, the usual answer is that it is accepted that at full roar the VCF takes about 6-7 HP.

This is equivalent to about 200watts. If you can find a 200watt fan and then have a battery and alternator to drive it, then go ahead.

If you only drive in town, you may be OK with a big alloy radiator and say 2 Falcon fans, but if you EVER get on a sand hill at 35Cplus, you will be wishing for a VCF.
Regards Philip A

Thanks to all, the viscous fan will stay.

Land Rover extensively test all cars in in Minus temps and Extreme heat more than most manufacturers. I think up to 55c in the Saudi / Moroccan Deserts from memory. Kept in good order standard cooling systems more than adequate in our climate. That said, we're a warm country and any weakness can be a problem.

Originally Posted by PhilipA

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I was thinking this through once again awhile ago and evolved a theory that once you get going over about 60Kmh the airflow through the radiator drives the fan anyway, so you would have little drag on the engine.

Crikey PhilipA, I know it's the silly season but really ...................... using this (lack of) logic I suppose that if doing 120 Km/hr then the engine can be turned off and the wind/fan turbine would power the vehicle ?

on another note

Originally Posted by PhilipA

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...................................the usual answer is that it is accepted that at full roar the VCF takes about 6-7 HP.

This is equivalent to about 200watts. If you can find a 200watt fan and then have a battery and alternator to drive it, then go ahead.

Back in the old days when I went to school 1 HP = 746 watts.
So that 6-7 HP would work out at around 5 THOUSAND watts or an extra 350 or so amps from the alternator (at 14.2 volts) to match it, ....................... hardly viable I would think.

But I reckon you're spot on with your conclusion.

Originally Posted by PhilipA

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..................................... but if you EVER get on a sand hill at 35Cplus, you will be wishing for a VCF.
Regards Philip A

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Couldn't agree more

Deano