Stuck viscous fan removal

hi guys

It appears my viscous fan has seized and runs noisy. Anyway I'm having trouble removing it. 300tdi 90

I have bought 32mm slim spanner fits on a treat and remembered its reverse thread but when trying to undo the coupling my engine / drive belt just spins I have left in gear hand brake etc but doesn't seem to make any difference also tried a few wallops with a hammer on the end of spanner still no joy.

Any tips ? Is the 32mm bolt you undo attached to the viscous unit (reverse thread) or used as a locking nut like on track rod end etc?

Thanks

Rich

It is reverse thread ...
if it is well stuck try giving the flats of the nut a sharp tap with a cold chisel to 'spread' the threads, it usually works ...

it is a lh thread on a 300tdi , it helps if you hit spanner with hammer to shock nut loose ,if that doesnt work hit each flat hard with a flat headed punch in the center of each flat after youve hit each flat a few times nut will come loose by turning fan

jamesmartin said:

it is a lh thread on a 300tdi , it helps if you hit spanner with hammer to shock nut loose ,if that doesnt work hit each flat hard with a flat headed punch in the center of each flat after youve hit each flat a few times nut will come loose by turning fan

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Nice to see you around James

Did this the other week - I used a Boa tool like this (http://www.ebay.co.uk/itm/like/2816...ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80) to hold the bit between the top pulley and viscous fan coupling with one hand whilst using the fan spanner with the other if that makes sense!

And having finally got it off, the question is - replace it or go electric?

haven't got it off yet haven't had the time or weather not keen on smacking the nut / water pump to hard so going to try the socket on the alternator trick to help hold the belt steady.

will replace with another viscous unit as don't want to add extra electrics to a simple machine.

trouble it what make to go for a genuine lr part is roughly £180 a ****part is £28 and there some middle ground makes any recommendations this units lasted 21 years ! so is it worth going genuine again.

Oldfogey said:

And having finally got it off, the question is - replace it or go electric?

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I changed my viscous for a Kenlowe electric. My thinking was in the winter time here it can drop down to -18C. I thought removing the Viscous might help the engine warm up quicker, and they say less drag increases fuel economy. Didn't make a scrap of difference. still took the same amount of time to warm up and no noticeable difference to fuel economy. I have gone back to a Viscous fan. After my last trip to Morocco with the electric fan which worked perfectly well I found I always had one eye on the temperature gauge and was wandering if it would trip in. On some long hills when the engine was worked hard the temperature gauge would go to just outside the red , but never went into it before the fan tripped in. I had to change my rad recently and decided to go back with the Viscous fan as no electrics to worry about. One advantage about electric fans is you have plenty of room to work around the engine bay. One other point worth mentioning is. The Kenlowe fan recommended for a Defender did not cool the intercooler, only the rad. Where as with the Vicous fan the cowling also draws air in through the intercooler. Although I could not fault the Kenlowe fan, I just feel more comfortable keeping things standard. I went for the £28 one.from Paddocks. The Original would have to last 6 times longer before you got your money back. So far so good. Morocco next spring so I will see how it all works out.

I guess the other consideration is that a viscous fails in the "on" mode - so may be working unnecessarily, but at least its working.

I think the electric fan fuel economy myth comes from a couple of places-
- Most modern cars have them. But then that's because most modern cars have transverse engines, so you can't have a belt-driven fan.
- Misunderstanding of fan power consumption. Even a fixed fan will draw less power at speed due to the airflow through the radiator- the airflow reduces the angle of attack of the blades and so reduces the torque needed to drive it. A viscous unit will be essentially off.
- Misleading bench test figures. If you test engines with different fan setups on a stationary rig, the lack of airflow will favour the on/off operation of an electric fan.

A brand new Discovery comes with an engine-driven fan. If there really was a fuel economy benefit then it would most certainly be fitted with electric fans instead. The only real advantage electric fans have is the ability to turn them off manually for deep wading etc. Otherwise viscous is just simpler and more reliable. If it does fail 'off', you can often come up with a temporary fix that will get you home.

I used a cable tie to round the belt to tighten it and stop it slipping, couple of taps with on the spanner with a hammer and off it came.

As previous posts used a socket on the alternator pulley nut and few taps with a hammer on the viscous spanner came off easy.

To put some off myths to bed have been running for a few hundred miles now with no fan at all I have gone for a genuine oem part from rimmer bros for £60 which should come in the post any day now.

Mpg no difference what so ever noticed.

Power gain or lack of with the seized unit on I had a slight loss in power and heavy stealing no doubt caused by the extra resistance against the belt and engine. With the viscous unit off its back to normal so no gain there.

With no fan fitted the temperature has been steady at just below halfway same as normal I have been sat in standstill traffic and giving a boot full of throttle just to see if it would creep up but seems good.

Another benefit with no fan is the car does appear to be quieter !