air con fans instead of viscous fan

I understand that the standard viscous fan drains power and ruins fuel economy and so have thought of a way to improve it without spending loads of money.
I have a 97 disco with air con and twin fans, the question i have for you is, can i remove the viscous fan and use the air con fans to push cold air into the rad to cool it.
If so would i be able use a water temp sensor to switch the fans on and off.
Or would i have to do it manualy, and if i go that route which wires would i have to piggy back into ?
Or should i stop messing around and just drive the thing????????????????

NIKNAK said:

I understand that the standard viscous fan drains power and ruins fuel economy and so have thought of a way to improve it without spending loads of money.
I have a 97 disco with air con and twin fans, the question i have for you is, can i remove the viscous fan and use the air con fans to push cold air into the rad to cool it.
If so would i be able use a water temp sensor to switch the fans on and off.
Or would i have to do it manualy, and if i go that route which wires would i have to piggy back into ?
Or should i stop messing around and just drive the thing????????????????

Click to expand...

Just a thought for you, I run both our Discos' without viscous fans - or any other fans for that matter. Both stay within normal temps.

I always keep a close eye on coolant levels and temp guages but both are fine - and both give good mpg !!

Cheers
Dave

cheers dave,
Do you use your disco for motorway driving or do you do much around town driving?
I do alot of around town driving then tow a twin axel caravan around over the weekend. Do you think i would be ok to remove my fan and still keep within safe temps?
Is it a big job to remove the fan and when done what sort of mpg increase can i expect?

NIKNAK said:

cheers dave,
Do you use your disco for motorway driving or do you do much around town driving?
I do alot of around town driving then tow a twin axel caravan around over the weekend. Do you think i would be ok to remove my fan and still keep within safe temps?
Is it a big job to remove the fan and when done what sort of mpg increase can i expect?

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Hi niknak, I use my Disco as my everyday transport so it does all the jobs, A roads, motorways, in-town driving, towing our horse trailer etc etc.

The temp NEVER budges from about one third on the dial.

I check the coolant level nearly every time I use her and it never varies.

The fan is always in the boot with the fan spanner, just in case.

To remove or replace the fan takes about 1 minute or less.

Re mpg can't really comment other than to say anything that's less of a drain on the engine is going to help - Kenlowe quote 8.50% improvement, well maybe .

Cheers
Dave

Thanks once again dave.
Will get the spanners out tommorrow, just one more quick question : Do you know where i can get a heat exchanger?.
I am going to put veg oil in it but need a heater to warm the oil up. I have seen various sites with a copper pipe from the water coolant with a micro bore tubing wrapped around it to warm the oil but i want one where i can fit glow plugs to it to quickly warm the oil in the winter then switch off when the coolant temp is high enough to warm the oil on its own.
Any ideas ????????
cheers.

Not exactly what you are looking for but VM diesel equipped Range Rovers had a heated filter housing which would partly do the job.

once again dave thanks for the info.
I`ll start looking around tommorrow.

NIKNAK said:

Thanks once again dave.
Will get the spanners out tommorrow, just one more quick question : Do you know where i can get a heat exchanger?.
I am going to put veg oil in it but need a heater to warm the oil up. I have seen various sites with a copper pipe from the water coolant with a micro bore tubing wrapped around it to warm the oil but i want one where i can fit glow plugs to it to quickly warm the oil in the winter then switch off when the coolant temp is high enough to warm the oil on its own.
Any ideas ????????
cheers.

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This has been said a million times so do a search. You DON'T NEED TO HEAT VEG OIL just pour it into the tank.

I saw something about a wiring in a pug205 twin electric fan somewhere...
anyone else heard or done this???

Ask Daft

or read this

Yes you can remove viscous unit and switch on the air con fans.

Yes it does make the engine feel more 'free revving'.

Yes it helps economy, more so if your viscous is sticking.

If you use the air con then the engine coolant radiator will have warm air blown on to it, not good on a hot day when the engine needs cooling.


You can make the fans auto by either:

1, X eng X-eng High Performance Off-Road Engineering sell a tube capable of taking a variety of fan switches. that fits in the bottom hose.

2, Drill the thermostat housing to take a fan switch.

3, Buy an adjustable thermo switch from Kenlowe, fit it in the top hose

4, SPAL offer a sensor type fitting that goes between the rad fins.

Whatever method you choose always fit a decent relay.

A manual switch is a good idea to turn off the fans if you ever get into deep water.

As pointed out the 200 and 300 tdi engines tend to run quite cool however I have found my electric fan is on and off quite a lot when off roading and at high motorway speeds.

If towing a caravan I would fit a Kenlowe or SPAL or even get to the Jap breakers yards, there is always a good selection there to choose from.

Make sure you get the right one i.e. sucker or blower. It is not a simple job to wire it backwards to change air flow direction as the blades are designed for one direction only.

regards

Dave

sucking in from behind the rad is the best option.

thebiglad said:

Just a thought for you, I run both our Discos' without viscous fans - or any other fans for that matter. Both stay within normal temps.

I always keep a close eye on coolant levels and temp guages but both are fine - and both give good mpg !!

Cheers
Dave

Click to expand...

Just a word of warning i use to own a 3.5l v8 carb disco with electric kenlowe twin fans. The car was in tip top condition but still if in traffic you switched the fans off the temperature gauge would go up to over 3/4.

Maybe it differs with later model disco's from petrol to diesel on how well the engine stays cool without fans. But personally its not worth the risk, its much better for peace of mind to be able to switch a fan on if the car gets hot.

It is much better to have electric fans instead of a viscous but just remember they use quite a lot of battery power when in operation and if set to automatic they will carry on running when the engine is switched off.

not if you put them to an ignition live.

robs said:

Just a word of warning i use to own a 3.5l v8 carb disco with electric kenlowe twin fans. The car was in tip top condition but still if in traffic you switched the fans off the temperature gauge would go up to over 3/4.

Maybe it differs with later model disco's from petrol to diesel on how well the engine stays cool without fans. But personally its not worth the risk, its much better for peace of mind to be able to switch a fan on if the car gets hot.

It is much better to have electric fans instead of a viscous but just remember they use quite a lot of battery power when in operation and if set to automatic they will carry on running when the engine is switched off.

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The V8 does run hotter than a diesel anyway, exhaust temps are a lot higher as well so fair comment with a V8.

Having the fans run after the engine is switched off is not as bad as is first appears. It helps with heat soak and the few minutes that they run on for should not bother a decent battery.

Mine are wired via the aux battery so not likely to cause a problem. To be honest despite the hot summers we have over here the fan hardly comes on at all except as mentioned in an earlier post i.e. off roading and high motorway speed coupled with a long climb up hills.

Raz mentioned sucking from behind the rad, if the fans are fitted close enough I do not think this is an issue in terms of cooling however, if you get into mud a lot and your fans are 'blowers' then it is easier to hose the rad fins backwards to clean them i.e. from engine side forwards, if a fan or fans are fitted engine side it makes cleaning te rad properly a lot more difficult.

Go for it, you will not be disapointed.

regards

Dave

its not a case of the fans being close enough or not, the air has only just exited the fan and does not carry as much speed (colder temps) as air that is already mooving into the engine bay and then bieng sucked through.

RAZ8550TDI said:

its not a case of the fans being close enough or not, the air has only just exited the fan and does not carry as much speed (colder temps) as air that is already mooving into the engine bay and then bieng sucked through.

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Sorry Raz you lost me! The fan definitley pushes or sucks more air (or rather the air in front of the fan) than if the car was actually moving at speed.

Am I missing something here?

regards

Dave

it moves air when car is stationary, this is when your car would overheat with no fan

Sirus said:

it moves air when car is stationary, this is when your car would overheat with no fan

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OK, I understand why a flow of air is needed for the heat exhanger or rad to do it's job. Regardless if a fan blows air into the radiator or sucks air through the cooling effect should be the same right?

It could be argued that the air may have been ever so slightly warmed from the heat of the fan motor but probably not even a factor.

I fitted my V12 Jaguar Coupe (manual) with twin fans as 'blowers' and then tried them as 'suckers' (swapped fan blades) and found no difference in the amount of time it took to cool the engine.

I could be missing something here, it is 36 degrees outside!

regards

Dave