Visco fan V's Electric fan

I'm in a dilemma. I'm going to change my Rad as is 25 years old. It's OK for normal road use but on a recent trip to Morocco the temperature gauge did creep towards the hot mark when going up long steep hills through the Atlas mountains. I currently have a Kenlowe electric fan which has worked fine.
Lets be honest a 200tdi on normal roads doesn't get hot. The reason I fitted a Kenlowe electric fan was to give me a quicker engine warm up time in the winter. Hand on heart It didn't make the slightest difference, nor did I see any difference in fuel consumption. I also have a brand new Visco's fan in a box in the garage.
My Dilemma is as I will be taking out the rad, should I refit the Kenlowe fan or the visco. My thinking is with the Visco fan there is less like anything can go wrong with it and that is what Land Rover designed it with. Or should I fit the Kenlowe. With the Visco and all the cowling the Turbo rad also gets cooled where as the Kenlowe's cowling only covers the actual engine rad. The Kenlowe has worked perfectly but being electric there is more that can go wrong with connections etc. I have full confidence in the Kenlowe fan itself. It has survived river crossings etc and the desert.
What would you guys do and why?

Well... If you do happen to get rid of the Kenlowe at the right price I might be interested?

Generally speaking, the viscous was probably engineered with mass costings and production in mind. Kenlowe have obviously done there research and believe their claims to be almost 100% true. Depends whether you want genuine LR or the "upgrade". Plus I know it's all in relation, but the Kenlowe is all fitted to go off and on... visc would initially be some work to refit wouldn't it?

Personally, would still go with the electric fan.
Been running my 200tdi with an electric fan for years now since the original viscous fan packed up. I find the reliability of the system lies in the simplicity of your connection.
Only downside I see is when the alternator belt fails and the fan running quickly drains the battery. With a viscous unit, you could probably drive all day with minimal electrics with no problems.

I always remove viscous fans IMO they are less reliable than electric and make changing belts etc much harder. P38 viscous fans are rubbish.

ifloochies said:

Personally, would still go with the electric fan.
Been running my 200tdi with an electric fan for years now since the original viscous fan packed up. I find the reliability of the system lies in the simplicity of your connection.
Only downside I see is when the alternator belt fails and the fan running quickly drains the battery. With a viscous unit, you could probably drive all day with minimal electrics with no problems.

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Alt belt on the def 200 also runs the viscous fan

J.A.P-LR said:

Well... If you do happen to get rid of the Kenlowe at the right price I might be interested?

Generally speaking, the viscous was probably engineered with mass costings and production in mind. Kenlowe have obviously done there research and believe their claims to be almost 100% true. Depends whether you want genuine LR or the "upgrade". Plus I know it's all in relation, but the Kenlowe is all fitted to go off and on... visc would initially be some work to refit wouldn't it?

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Nope, The Visco just screws on and then two bolts to hold the cowling in place. Probably less work than fitting the Kenlowe back in place.

mikescuba said:

Nope, The Visco just screws on and then two bolts to hold the cowling in place. Probably less work than fitting the Kenlowe back in place.

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And in the case on mine took hours to unscrew

Datatek said:

I always remove viscous fans IMO they are less reliable than electric and make changing belts etc much harder. P38 viscous fans are rubbish.

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Yes, there is much more room to work on the Belts and water pump etc. The Kenlowe did its job in the desert without any problems and it does seem a solid piece of kit. It's been on my defender for about four years now. In normal conditions on the road I have only heard it come on a couple of times. In the desert it came on a lot more, especially when the engine was worked hard in deep soft sand.

Datatek said:

And in the case on mine took hours to unscrew

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If you have the special spanner it comes off easy.

Viscous fan works perfectly well and is the logical approach for a longitudinal engine. I think electric fans are only really common due to the prevelance of front-wheel drive cars, which obviously make a belt-driven fan impractical.

The whole fuel-saving electric fan thing is a myth anyway, as the power to drive the fan has to come from somewhere, which ends up right back at the alternator belt. The whole point of the viscous coupling is to reduce the drive to the fan when it's not needed, and once you're moving at any reasonable speed the flow of air through the radiator will remove any remaining load on it. Difference to warm-up time in winter should be minimal as there will be next to no flow of coolant through the radiator until the engine reaches operating temperature.

With the right spanner it's no trouble at all to take the fan off to get access- certainly easier than removing an electric fan from the same area. I can't see why you'd want to remove a self-contained system that has nothing wrong with it. The only time electric makes sense is if you're doing lots of wading and want a kill switch wired into the fan circuit.

Definitely electric fans for me - the fuel saving along makes it worth it at least 2 mpg.

Your cooling fan is only really needed in traffic / slow driving . Whenever you are doing any speed, the air flowing in is ample to cool the engine. So the visco fan is wasting energy.

I've changed from visco to electric on several vehicles now, my transit, my v6 Granada, and my v8 RRC.

Every one has shown an improvement in fuel economy.
Also, it's quieter.

I fitted a two stage system on my RRC, that came on low at about 75 degrees, and high above 90. This reduces underbonnet temps and any thermal shock.

In eight years, it has come on "high" perhaps a handful of times.

I wouldn't entertain a visco any more...

The weight of the visco fan put's more strain on the water pump bearings, more so if fan gets unbalanced.

I'm old school, go somewhere remote like you do Mike, fan motor dies, what then? I know a viscous can be made to lock up and run permanently in drive with a couple of wood screws.

I looked in to twin electric fans for my Td5, but it looked like I was replacing a simple mechanical fan with yet more wiring, fuses, thermostats and more potential for failures in Morocco.
I don't give a toss about MPG figures, loosing a couple of MPG over a reliable system wins for me.

do yu go wading?

I know where you are coming from.

You are right, the electrics can fail - but so can the visco couplings, and when they do, if not caught early, they can take the rad out, or in very rare cases, detonate, spitting blades out ( yes, I have actually seen this on a new supercharged Rangie, when the visco locked up,the fan came apart at high engine revs, cut the top hose, and left a blade sticking out of the bonnet)

Horses for courses, and personal choice.

If you are driving across hot deserts, then the visco fan is probably a good idea for cooling efficiency, as the fan will be needed a lot, and might well be my choice for an expedition. In the UK, my cooling fans rarely come on at all, and I preferred the quieter drive, more athletic feeling engine and fuel saving.

If the reliability of electrics concerns you, it's perhaps worth considering this - the TD5 has an electronic engine control, and you cannot fix that with a few wood screws if it goes wrong! you are already relying on a system that cannot run without the ECU!

The viscous fan only drives , and therefore uses energy when it locks up caused by the heat coming thru the radiator, at which point it is needed , and will deliver more cooling quicker than an electric fan . There is less to go wrong . Even in Australia the viscous rarely locked up , and even then for relatively short periods (thats with a good radiator) .
When cold they just windmill , you can even stop them with your hand , not that i recommend that you try
If wading the viscous is not locked even in warm creek water , from my experience !

Not strictly true.
The viscous coupling doesn't fully disengage, so always presents a load to the engine, and this load is not insignificant.

Regards wading, this is more of an issue to engines with spark ignition - less so on diesels.

There are pluses and minuses to both.
Viscous couplings an and do fail.

captainbeaky said:

Not strictly true.
The viscous coupling doesn't fully disengage, so always presents a load to the engine, and this load is not insignificant.

Regards wading, this is more of an issue to engines with spark ignition - less so on diesels.

There are pluses and minuses to both.
Viscous couplings an and do fail.

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If it doesn't there is something wrong with yours

Does the fan go around when the engine is cold?
If it does, then the viscous coupling is transferring some power to the fan - it's the very nature of the beast - there is always a parasitic load.

Incidentally, at colder temperatures, this load increases, as the oil in the viscous coupling is thicker when cold. My RRC and ford Granada used to make a terrific roar when started at very low temperatures, until the visco coupling warmed up a little and loosened up.

You might think that it's not a lot of load, but it's always there, and increases with engine speed, so has a bigger effect on higher revving petrol engines than diesels.

Like I said, there are pluses and minuses to either system.

I've had both in various vehicles, and for my tuned 4.6 v8 in the UK, I prefer the electric fans, for quietness and economy - especially with a two-speed or variable speed setup.

On a lower revving diesel, the losses will be less ( slower engine speed versus the petrol) and the noise would be less of an issue, as the diesels are comparatively noisier than the petrol engines.

Very few manufacturers use them now, in the desire to remove every last bit of unnecessary engine load in the search for better economy. When they do, they usually add an electronic clutch to them to properly disengage them ( as per the jag engined L322's).

Viscous versus electric fan - take your pick, there are pros and cons to either.