Viscous fan drive

My 90 2.5 TD starts to creep up the temperature gauge if left idling for a while, or when towing up a steep hill. The fan is stiff to turn when cold, but seems pretty easy when hot.

Would any one with more experience than me care to confirm that this is:

- a usual failure mode for the viscous coupling at 14 years of age

- best cured buy buying a new one (I don't want to bother with fitting an electric fan).

Thanks

Nick.

Reply to
Nick Williams
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Sounds to me like it is as you suggest "a usual failure mode for the viscous coupling at 14 years of age" Same thing happened when I had a Suzuki Vitara.

I picked up a nice cheap electric fan from a 2.0i Vauxhall Vectra (£20 from local scrappy) Fits like a glove, does a superb job. I now have loads of room in the engine bay as I have dispensed with the huge plastic fan cowling.

I really wouldn't bother fitting a new viscous one. It costs more and it does not take very long to fit an electric. But new electric one can be expensive (eg Pacet or Kenlowe)

Stew.

Reply to
90ninety

Fan from Vectra fits LR, NOT vitara - just thought I'd clarify!

Reply to
90ninety

Viscous units are they way forward though if it regularly gets wet and muddy. A few of my mates have put electric fans onto 200 and 300tdi's and they have to arse about turning them off before wading through deep water etc and then switch them back on afterwards.

Viscous are good cos you just forget about it. The worst that heppens is your engine bay gets seriously splashed / dirty rather than overheating when you forget to turn the leccy back on!

I can see the merits of electric fans (I went through this same process about 3 months ago) - i chose to replace my failing viscous unit with new - No probs now.

Reply to
Jon

On or around Thu, 30 Sep 2004 14:10:37 +0100, "90ninety" enlightened us thusly:

just beware of the fact that if the electric fan motor packs in it can leave you with no cooling on a hot day - this happened to mine a bit back, so I fitted a fixed engine-driven fan.

Viscous one on the disco seems to work - it does the spinning down a few seconds after startup bit, not actually got it hot enough to tell whether it spins up again.

Reply to
Austin Shackles

The WORST thing that can happen is the viscous fan, which you can't stop, sprays water directly onto your ignition coil, and liberally douse s the dizzy. An on/off switch is a small price to pay.

Steve

Reply to
Steve Taylor

The other plus going electric is the extra horse power you gain. Even a visous fan draws quite a bit from an engine

Reply to
Simon Mills

On or around Thu, 30 Sep 2004 21:52:37 +0100, Steve Taylor enlightened us thusly:

'course, that's why it has a cowling on it :-)

but it's a pity, really, that the dizzy on the V8 isn't where it is on a Ford Cologne V6, in between the banks at the back of the block.

Reply to
Austin Shackles

...not on 101s it ain't.

Steve

Reply to
Steve Taylor

Do you mean that when starting from cold the fan will spin up and then stop while the engine is running?

I hope not cos that means that mine is buggered, it goes all the time. It is a bit stiff to turn with the engine off but not seized. I thought that it was meant to turn all the time and would sort of 'lock up' as the temperature increased.

Bugger!

Reply to
Simon Barr

On or around 1 Oct 2004 13:31:00 GMT, Simon Barr enlightened us thusly:

I've only ever seen 2 that do it. In theory, it should spin initially and then slow down and just idle, it shouldn't spin fast again until or unless it gets too hot. When you fire it up, on mine, you get a lot of fan noise over about 2000 revs, then as you go along you can hear it suddenly slow down, and revving the engine doesn't make an accompanying roar from the fan. As I say, I've not had this one hot enough to find out whether it locks up again. On the Ford sierra V6, the fan does the same, and that one does lock up again, 'cos I've seen it do it while running it at 3000 rpm stationary for tuning the gas system; however on that engine it didn't spin up again until it'd got to the red at the top of the temp gauge.

does it spin fast and noisy all the time? It never actually stops, just runs slower. On car-sized ones, it's hard to spot that it's going slower, bar for the noise. I've seen great big buggers on truck engines, and they really do just loaf around slowly when disengaged.

Reply to
Austin Shackles

I don't think it is spinning fast all the time. I know what the noise sounds like as on the Niva the fan was going constantly. Occasionally I can hear a fan like noise, but its a bit hard to tell sometimes with the air intake being on the drivers side wing, it can be noisey itself.

I'm going to try and compare it with others on the next laning trip, see how much resistance, etc others fans give when the engine's switched off.

Reply to
Simon Barr

On or around 5 Oct 2004 07:47:16 GMT, Simon Barr enlightened us thusly:

I don't suppose you're near enough to listen to mine...

try it with the bonnet up - start the engine, jump out and rev it up a bit, you'll soon see/hear if the fan's running at full speed.

Reply to
Austin Shackles

Frayed knot.

I shall try this later. Cold would be best as it definitly shouldn't be locked up then.

I very much hope it's not buggered as I should really be replacing the vacuum pump soon and a visvous unit isnt cheap.

Was hoping to get some mud tyres soon too.

Reply to
Simon Barr

On or around 5 Oct 2004 09:32:55 GMT, Simon Barr enlightened us thusly:

if it's running all the time you can safely leave it, I reckon, all it might be doing is wasting a bit of fuel and making a bit more noise.

Reply to
Austin Shackles

Been out to check and I reckon it may be OK after all. It is spinning but when you rev the engine the fan doesn't seem to speed up as much as the pulley the fan is driven off does. All done by eye and not very scientific but it has put my mind at rest for now.

I was a bit worried about it being overcooled now the weather is turning.

Reply to
Simon Barr

Missed the begining of this thread so apologies if what follows is irrelevant.

When I replaced the viscous fan on my RRC I was told by the bod that services it that you can stop a viscous fan spinning on a cold engine with finger pressure alone. But he then added that you do this by griping a blade BEFORE starting a cold vehicle.

Be that as it may; regarding what you say about overcooling; before fitting the Kenlowes the engine temperature never varied once at operating temperature. Now going down long motorway-type hills the temperature drops significantly, say to about 25% of FSD on the gauge. Anyone able to explain that? No loss in heater performance tho.

Richard

Reply to
Richard Savage

On or around Tue, 05 Oct 2004 19:23:59 +0100, Richard Savage enlightened us thusly:

iffy thermostat.

actually, saying that, which engine?

the Perkins Prima Di I had in a minibus some while back would, if left idling in cold weather with the heater on, drop down to C on the dial. The heater actually provided more cooling than the idling engine created heat.

I took the fan off that one altogether with no adverse effects. No turbo on it mind.

Reply to
Austin Shackles

RRC + 3.5 V8i and new thermostat!

I wondered if the shroud on the viscous fan setup actually restricted the airflow; i.e. the engine block and fan sort of sits in the narrow bit of the shroud and perhaps slows the air through the rad ensuring that it doesn't cool at it's maximum potential. Engine doesn't overheat because of the viscous fan. Removing the viscous fan and it's shroud results in a less restricted air flow through the rad resulting in the rad being able to overcool the engine.

Richard ;-)

Reply to
Richard Savage

The safer method being stick a carrot into the blades. If it's working properly it should slice the carrot, if it's not turning effectivly the carrot will stop it.

Personally I hate viscous fans, too unreliable, and no backup when they do fail.

Alex

Reply to
Alex

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