Viscous Fan help please

On our way to Billing last week - had an issue with the old girl overheating. Normally the needle never moves, but up a large incline hill, fully loaded to the hilt must have been too much for her, as she then struggled to gain speed and needle shot up when I got onto the motorway afterwards.

I put heaters on full heat and blowers, slowed down, and the temp went down and she came back to life.

Have checked all usual suspects: coolant, re-bled the system, radiator etc. Last night checked my fan, and yes it does turn (so not seized on), and turns easy when cold, so nothing new there, but got the engine well up to temp and the fan never increased in speed. Stopped the engine and it still turned freely, so reckon the viscous part is either knackered or on its way out, which would explain the overheating when the engine is working hard and also on the motorways.

So, do I just put on a new complete viscous fan - £43.00 delivered, or go down the route of the electric fan with a thermostat in the top hose or an electrically adjustable thermostat for £69.99 delivered. Which thermostat is more reliable and better??

http://www.ebay.co.uk/itm/230665023518?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

http://www.ebay.co.uk/itm/14-Electric-Cooling-Thermostat-Radiator-Fan-Kit-LandRover-Discovery-1-300-Tdi-/230974879527?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3ADiscovery&hash=item35c72cf727#ht_3525wt_722

http://www.ebay.co.uk/itm/Electric-Radiator-Fan-Kit-LandRover-Discovery-1-300-Tdi-Thermostat-Adjustable-/220892133347?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item336e3277e3#ht_2945wt_722

I have read all the threads about fans, and seems it’s debatable to which is best.

So anymore thoughts which way to go? I know people have put on Mondeo or pug fans, but prefer to get a new fan and not someone else’s problems, if you know what I mean.....don't fancy completely cooking the engine

Anyone near the Bath/Bristol area with an electric fan fitted that I can have a mooch at??

I fitted a 14" electric fan on my 300,It was one of the cheap ebay ones.I was going to get an X-Eng thermostat for it,but to be honest I haven't used the fan yet. Sound likes there's more going on than just a dodgy viscous fan.

One of the first questions asked by the guy who is leading our group in Morocco this year was; "What type of fan have you got fitted?"
When I told him I had a factory standard viscous, he said; "Good, you've got the best item for the job. Anything else on the 300tdi's has proved to be a pain in the arse in the past."

Given he's been leading groups over there several times a year since 1982, I pretty much valued this opinion over anything else I've ever read on the subject.

Mark L said:

One of the first questions asked by the guy who is leading our group in Morocco this year was; "What type of fan have you got fitted?"
When I told him I had a factory standard viscous, he said; "Good, you've got the best item for the job. Anything else on the 300tdi's has proved to be a pain in the arse in the past."

Given he's been leading groups over there several times a year since 1982, I pretty much valued this opinion over anything else I've ever read on the subject.

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I do agree totally,but for the use I give mine electrics fine

MPfive said:

I do agree totally,but for the use I give mine electrics fine

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'Tis a fair comment.
I think it's fair to say his experience of them is more extreme climates and high temps.

Mark L said:

'Tis a fair comment.
I think it's fair to say his experience of them is more extreme climates and high temps.

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Totally,If I was going abroad or doing some heavy overlanding I would fit the viscous back on in a heartbeat. I do think there might be more going on to Stu's than just needing an upgrade or new fan,but if it went back to normal it might just be the fan not locking properly.

I ran a 300TDI discovery without a fan at all for months. I even towed a trailer with another disco on it for an hour and a half in summer with no problems at all. A 300 with a good radiator etc should be ok without a fan, i was skeptical but i have tested it myself so i know. It sounds to me like you need to check your water pump, but more importantly your radiator as what you describe just should not have happened. Forget the fan for now and check everything else out.

I run my Disco without a fan too but only on the road, although I have put it back on for this 'heat wave' we've had, just in case...

I upgraded to a full width Allisport rad last year, so pretty much giving it the best chance possible too.

Mark L said:

One of the first questions asked by the guy who is leading our group in Morocco this year was; "What type of fan have you got fitted?"
When I told him I had a factory standard viscous, he said; "Good, you've got the best item for the job. Anything else on the 300tdi's has proved to be a pain in the arse in the past."

Given he's been leading groups over there several times a year since 1982, I pretty much valued this opinion over anything else I've ever read on the subject.

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I think that's made up my mind. I do look at upgrading parts when they die, as lots of things have improved over the 17 years of the old girls life, but think i will just replace like for like this time. Plus it will keep a constant flow of air unlike an electric which is on and off.

Thanks again for the input

More than welcome.

Mark L said:

I run my Disco without a fan too but only on the road, although I have put it back on for this 'heat wave' we've had, just in case...

I upgraded to a full width Allisport rad last year, so pretty much giving it the best chance possible too.

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On your way to billing when it overheated. I am guessing you were on the road (with the fan). The allisport rad is good i guess, but do you take the car offroad? It might just need a really good clean. Or as i said the water pump. Have you by any chance been playing with the pump etc? This can increase EGT and i never ####ed with these things too much as you are generally asking for larger fuel bills and more trouble. I have always kept my disco's standard (as far as engine is concerned) right down to the EGR and never had any problems other than HG due to a knackered radiator.

Your reply doesn't make sense to my post...

Mark L said:

Your reply doesn't make sense to my post...

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which part?

I used to have the same problem with my 300 Tdi untill I changed the rad. Now, even if pulling hard up long hilld the temp guage dosn't move. I tow a heavy twin axle 'van and have to negociated long inclines when leaving Cornwall. My best suggestion is to check the rad and replace if required and keep the viscous fan. Also remember that the viscous coupling requires a good rad to blow heat onto it. If the rad is not good the air passing through it will not pick up enough heat and the fan won't engage properly.

Just a thought.

Philip0603 said:

I used to have the same problem with my 300 Tdi untill I changed the rad. Now, even if pulling hard up long hilld the temp guage dosn't move. I tow a heavy twin axle 'van and have to negociated long inclines when leaving Cornwall. My best suggestion is to check the rad and replace if required and keep the viscous fan. Also remember that the viscous coupling requires a good rad to blow heat onto it. If the rad is not good the air passing through it will not pick up enough heat and the fan won't engage properly.

Just a thought.

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Thats a good point. Any other way to check the viscous fan before i change maybe a good one instead of using the money for a new radiator?

bananahead said:

which part?

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Sorry mate, I was referring to the post directly above my last one.

I think he has confused you with me having the problem.....

Do you think if i use a heat gun on the fan it will be hot enough to tighten it up so i can dismiss that as being at fault, or will it be too much heat and knacker it?

Over the last year my disco has overheated a couple of times. I've towed heavy loads with no issues then randomly it would overheat.

I was a bit confused as after replacing the water that had gushed out the header tank it would be fine for months. I thought it might be the cap, and I will replace that with a new one soon.

But on the way back from billing my Cambelt snapped.

I decided that whilst replacing that I would do a full service and remove the rad to flush it through and change the coolant.

Well I didn't need to remove the rad, when I took the top plate off I could see leaves between the aircon rad and main rad over half way up. I've done a lot of fording in very deep water since I brought the truck, and these leaves turned out to be twigs, leaves and mud that came out in clumps from there.

I am certain this will be the cause of my problem as I effectively only had half a rad working.

If you have aircon then its worth a look behind there.

Stu, you will know if the viscous coulling has gone by the incredible noise it will make. Sounds like a bucket of bolts in a washing machine. You could try this simple test:- lift the bonnet, ensure that all is cold then start the engine. Fairly quickly rev the engine to about 2000 and you should hear the fan initially roar then quiten down. This is the viscous coupling 'un-coupling' as it takes a moment or two for the oil in the coupling to start to work. If it is doing that then all OK. The viscous couplings are very reliable. In all my 30+ years I have only had one fail. I would, as you have the auto definatly stick to the viscous coupled fan. Due to the age of your Disco, which is about the same as mine then it will be due a new rad as the origional will be copper and this degrades over time. Hope this is of help.