[The Mad Hat Man]

I beg to differ James - there are alot of peeps on here that have fitted leccy fans and say they rarely if ever come on.

theraml shock is relative and can be altered by the switching mechanism of the fan.
Lots of vehicles only have leccy fans, particularly those suffering extreme stress and temperatures, such as in performance vehicles. Cant all be wrong.

Mind yu - i agree, that if yu are wading then it comes into its own.

 

[jamesmartin]

of course they rarely come on ,air flow in moving vehicle is enough,as viscous mostly free wheels ,leccy fans do offer more thermal shock as its all or nothing ,but thermal shock unless massive is a relative long term shortening of hg life ,most vehicles are transverse engined ,so leccy fan is only one that could easily fit ,i cant see the point of changing from perfectly good viscous fan unless wading or fitting disco 200 tdi engne in series or defender dictates it as necessary or an upgrade

 

[jamesmartin]

well i read a couple of paras and gave up when i read that a big fan wont cool the engine below the termostat opening temp.... that is wrong.... i had a renault 19 diesel which we used to low a 4 berth caravan...temp would rise towards the red on long hills, . leccy fan on the rad only cuts in when the temp gauge hits the red... so fitted a switch to turn the fan on manually.... hitting some of them long hills on the a30 in devon with the gauge at approx half , turn the fan on at the start of the hill the gauge was well lower at the tops of the hills.... if hes made a basic mistake like that you cant trust anything else in the article.


as i understand the disco 1 aircon theres a thermo switch top front of the head that turns the aircon fans on when its too late... a switch accross that (so the two are in parallel) will turn the aircon fans into manually oporated cooling fans with the thermo switch as back up if you miss turning them on manually. you then can fit another switch in series ( cut any of the existing wires ) to turn the system off for wadind

id be interested to know why you think thermostat doesnt control engine temp

 

[The Mad Hat Man]

I am now more confused.
I didn't think that rich was saying that, James. However turning on a fan with the thermostat shut won't cool the engine much as there is little circulation of the coolant.

 

[jamesmartin]

I am now more confused.
I didn't think that rich was saying that, James. However turning on a fan with the thermostat shut won't cool the engine much as there is little circulation of the coolant.

said the man was talking bollocks ,he wasnt a big fan cant cool below thermostat opening temperature,thats the whole point of thermostat

 

[The Mad Hat Man]

To a degree, yes. But it isn't the only thing that controls engine temperature. Which is what the article also stated.

 

[jamesmartin]

to a degree ? it does ,you may use either leccy or viscous or fixed or just air movement to cool rad .but thats a different argument

 

[UKAirborne]

:whoosh: my head hurts.. I didn't think this subject was that complicated, until now

 

[The Mad Hat Man]

It's not complicated....
To answer the OP....... Yes, tiz easy.
The rest is personal preference and bias.

 

[Diesel Do]

OMG!
The viscous fan cools more efficiently than a Kenlowe. If doing expeditions across the sahara even Kenlowe say keep your viscous fan but supplement with extra cooling if necessary, ie extra fan, bonnet extractor etc
Electric fans are easy to fit, take up less space, are more than adequate 99.9% of the time, may increase economy/performance by a very small amount, you can turn em off for wading, I don't think noise is an issue,
Why would you want to cool below stat opening temp? The whole point of the stat is to get the engine to the correct operating temp ASAP and maintain it to reduce wear and for efficiency! If the temp does drop below the stat temp it should just close, stop water going to the rad and stop the fan working whether viscous or electric! The fan should cut in/out a few degrees higher than the stat opening temp. Forward motion will provide far more air than a fan can provide (at a reasonable speed) and can easily cool below stat temp, that's why the stat closes to maintain engine temp at optimum! Try driving down the motorway wit a stuck open or removed stat, the temp plummets!
I believe that in general thermal shock is a negligible issue, unless you own a 1.8 freelander, in which case you're stuck with the electric fan any way, this is due to a very small amount of water being in the engine which can be completely swopped for cold water very quickly effectively shrinking the engine, this was improved with the stat mod which blends hot and cold water returning to the engine so as not to shock it! Hopefully! Proper engines hold enough water for this to not be much of an issue?
Basically unless towing a trailer across the Sahara in low range.............. It just comes down to personal choice, there are pros and cons to both! So stop thinking too much!!!!!!! W

 

[ricc]

if you read my post about towing with the renault and leccy fan ..... ive seen the temp gauge go down from normal to the bottom stop whilst towing up long inclines on a hot day...... i can only assume that the airflow from the leccy fan after passing through the rad hits the side of the transverse engine block and cools it and the water in it (which is what the temp gauge is measuring)directly..... seems logical to me

all the modern cars with leccy fans ive driven , its been rare for the fans to actually come on..... usually only when the cars stationary after a hot run....and all them only seem to come on when to me the engines already over cooked..... perhaps thats why blown head gaskets are more common now than they were 30 years ago. ive also seen cars running happily with the leccy fans seized solid(cos they never come on)

 

[jamesmartin]

generally true, my point is that what the bloke in article said he didnt get wrong ,so read the rest of article you may get a better understanding ,with a fully functioning thermostat larger fan size wont cool below operating temp,thermostat does control temp ,yours may well have not been shutting fully it is very common, and temp guages arent calibrated thermometers, but doesnt take away from priniciple you dismissed ,i thought he gave unbiased view,how else would you cool transverse engine, the best form of cooling is to maintain a steady temp (operating temp)not hot ,then cooled quick then hot

 

[Diesel Do]

generally true, my point is that what the bloke in article said he didnt get wrong ,so read the rest of article you may get a better understanding ,with a fully functioning thermostat larger fan size wont cool below operating temp,thermostat does control temp ,yours may well have not been shutting fully it is very common, and temp guages arent calibrated thermometers, but doesnt take away from priniciple you dismissed ,i thought he gave unbiased view,how else would you cool transverse engine, the best form of cooling is to maintain a steady temp (operating temp)not hot ,then cooled quick then hot

Agreed! Think that's wot I said in a round about way

 

[ricc]

jm ... youre assuming theres no heat loss from the engine block itself.... im saying my experience suggests that with a leccy fan running the airflow over the block will cool the water in it . ...even if the thermostats shut and no water being pumped to the rad.

 

[jamesmartin]

your assuming that ,obviously on a transverse engine it would have some effect but not as great as you assume ,id be interested to see you block off rad and try it ,what matey says is in principle true ,apart from were talking about tdi which is not transverse and is fitted with a perfectly good fan already which only limitation comes with wading

 

[ricc]

your assuming that ,obviously on a transverse engine it would have some effect but not as great as you assume ,id be interested to see you block off rad and try it ,what matey says is in principle true ,apart from were talking about tdi which is not transverse and is fitted with a perfectly good fan already which only limitation comes with wading

so james what in your opinion is the cause of a temp gauge going down well below normal when the leccy fan is turned on on a 1.9 diesel car pulling a 4 berth caravan and family of 4 up a long hill on a hot day at low speed in heavy holiday traffic if its not the airflow from the fan cooling the water?

 

[jamesmartin]

do you know if thermostat wasnt stuck open ,do we know if your exaggerating ,of course a fan will cool rad ,the bigger the fan output the quicker rad will be cooled,thats not the crux ,going read the whole article and similar with open mind ,then you know theories behind what you see

 

[50 pence]

I think a lot of people belive that LR just bolted a massive fan onto the front of the engine and connected it by a belt to the crank, thus sapping vast amounts of engine power.

The reality is that the viscous coupler part of the fan assembly is quite a clever, but simlpe bit of engineering.

It is my opinion, that a correctly functioning viscous fan, for 99% of what these vehicles get used for, cant be bettered.

Any savings is fuel are negligable, swallowed up by the cost of the installation anyway.
You,ve then got the added risk of an electrical failure, which could be catastrphic for the engine. ( I also think its funny that so many people steer clear of the later TD5 Discoveries because of, " all the electrics ", to only go and put an electrical cooling system on a " simpler " vehicle ).

I can stop my viscous fan turning with the engine running with a bit of rubber hose, ( obviously NOT while its really hot ! ), thus proving that, most of the time, the fan is freewheeling.

I cant speak for the 200,s or 300,s, but its a real eye opener looking at the temperature on live data on a diagnostics machine, when driving a TD5 WITHOUT a viscous fan. The temperature is very up and down.
With the viscous fan fitted, the live temerature data is very stable indeed.

Again, these are just my opinions based on what I know about the subject, and there is no " right or wrong ", just personal preference.

Cheers.

 

[jamesmartin]

exactly mr 50 pence,

 

[Sheffield]

One small advantage of removing the viscous fan and fitting an electric fan is it improves the access to the front of the engine and makes changing belts etc easier, and it is one less thing to get fingers and clothes caught in while fiddling with the engine running.