A fan question

I replaced the viscous fan in my disco when i bought it. And while i was at it i also replaced both electric fans at the front on the condenser as they weren't working as well.

I ran a manual switch from the thermo switch that turns on one of the electric fans when the engine overheats.

So now if i am crawling through sand or mud or hills i flick the switch in the dash and the electric fan turns on as well. It is still wired up to come on all by itself if the engine overheats though. These V8s need their cooling.

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Originally Posted by DazzaTD5

A functioning viscous fan will lock up at low rpm and still draw far more air than aftermarket electric fans.

More demanding slow driving in heavy sand, where vehicle is moving slow but engine rpm are higher, again the viscous fan will be far better than electrics.

Land Rovers of old have always had a good cooling setup with the viscous fan and the electrics (twin on old, single on newer) that as mentioned turn on with temp and also with a/c on.

Regards
Daz

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A VC, even when locked up, will depend on engine speed. An electric setup does not. Just about every vehicle made in the last ten years uses electric, and they all seem pretty reliable.
I appreciate that there are other factors in play these days. For example, BMW, of all makers, are fitting electric power steering, in order to meet emission standards. However, fans have been electric for far longer than that.

These days, with under bonnet temps as high as you will ever see them, and engines tuned to a state that would have been incredible even ten years ago, do you see VC fans? On a RR? On a Ferrari? Does Bugatti fit one to each of the ten radiators on a Veyron?
In fact, who uses a VC setup these days, anywhere?

Yes, some trucks still do. The R730 I was driving had one, and it needed the electric ones as well to help it on hills, because the load was high and the revs were low, and the revs were low because that's where the torque is.
Yank trucks use the Horton fan, and they are probably the most problematic device ever fitted to a vehicle ( well, unless it's a Freightliner ).

Sorry, you fail to convince me. And I must add, I didn't mention after market. The Ford fans are very good. Can't speak of others.

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Originally Posted by PhilipA

I once saw an analysis that said that a Range Rover viscous fan drew about 7Hp when locked.

If you work out how many amps that is at 12volts it is about 400 amps.

7Hp =5291 watts Divided by 12 =440amps

Now show me some 200amp fans if you have 2 of them.
Regards Philip A

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Do you really care what the drain on the alternator is? Does it matter to you that a 2.7 tonne truck draws a couple more amps?? Pretty sure I don't.

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Originally Posted by Roverlord off road spares

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You're having so much fun, I reckon there should be a commission. Laugh that up:angel:

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Originally Posted by Roverlord off road spares

If it ain't broke why fix it, that's probably why land rover stuck with VCs instead of ditching them and going all electric

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Did they?? Is there a VC in the new RR? The new Disco?? I'm happy to be proved wrong. Will I be??

Strangely, a very simple search comes up with a huge hit in Oh So Reliable Toyota and VC fan issues. Say what you like about Toyota, If they can't get it to work, well what can I say..

I've had EL Falcon twin thermo fans on my V8 for about 4 years now, along with a Delta Current Controller with a knob on the dash which lets me dial in what temperature I want the engine to run at.

The controller ramps the speed of the fans up and down to maintain a very stable operating temp. On full pelt the fans pull around 3,000 cfm of air through the radiator. A small light on the dash changes colour depending on how fast the fans are moving (green =off, orange = medium on, red = full on).

It never overheats, and is quieter than the old VC and so far very reliable. Also releases a small amount of power.

The downside (apparent) I have seen thus far to VC fan is the cycling it goes through in hot weather or when under a heavy load. I monitor the VC fan speed digitally and watch it in relation to coolant temp via madman. 300tdi.

The coolant gets hotter, then the VC fan gradually speeds up to max ~2250 rpm, brings the coolant temp back down and then gradually releases back to around 1000-1200 rpm..at 100km/hr road speed (under bonnet temp about 35- 75C - depending on outside air temp). Then the coolant temp gradually starts to rise again (as the VC fan has gone to low speed)...and the cycle is repeated. Probably about 6-8C variance between high end and low end. I'm not sure that's great for the head gasket. A fully electric setup (designed to give enough air flow) could monitor coolant temp and change fan speed to maintain the coolant temp within a tighter temperature range (within reason) - rather than have this cycling thing going on.

I just read your comment Traco.....exactly what I was thinking....great to see it works.

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Originally Posted by Roverlord off road spares

Danny you have an electric fan in front of your rad, it is activated by the sensor on the thermostat housing.
As for fitting fans to replace the viscous coupling, people have experimented with EL falcon fans, but if I recall they are ok for normal driving, but for off roading they are useless and you need a viscous driven fan. Do a search I recall there was a post of why they are not that good.

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I have run twin ford fans on mine on and off for years, they are reliable, help with fuel economy, acceleration and noise

But when the going gets tough go back to the original fan, I am getting a high volume t/stat for mine I will have it installed in a couple of days and I will put the electric fans back on and see how that works

New Tstat fitted it's an 88c one my original LR one was 84c so I left the fans to come on at 84c


On the road it runs at 83c much more than before but I haven't really tested it under load