Double fans

[BigBertha]

hey i was wondering if i put an electric fan in front of the radiator fo use when offroading or towing to make sure it stays normal temp and use the existing viscous fan for normal use will that work???

[shortylux]

I have heard a figure that anything above approx 30kph then the fan does nothing. Also you might find that your mechanical fan moves much more air than the electric, such that the electric is a restriction or has no effect. You would have to try it to know for sure though.

[BigBertha]

thats what i was thinking,will have to get quite a powerfull electric fan to match the viscous. yea mite give it a go some time, it dosent overheat but just want to prevent it if something goes wrong. cheers for the info tho.

[oldyella]

I think you would be better purchasing a new viscous hub if you are having overheating issues or have concerns.

I wasn't happy with how my viscous fan hub was keeping my V8 LR cool so I purchased a new hub.

Now all I can hear is fan noise. I'm actually going to have to cut the muffler out and just run a resonator so I can hear the V8!

Definitely not going to have overheating problems now

[3VILC]

So far as I know (at least thru researching computer cooling), one fan pushing and one pulling (over the same area, ie. thru the back of the fan shroud) will not move any more air than one by itself. Infact as mentioned before the lesser flowing one would probably actually hinder the other. For any gain both fans need to work in the same direction side by side not one behind the other.
Such as these showoff computer cases that have fans everywhere, eg 1 fan pushing air in the front and one drawing air out the back of the case doesnt flow any more air than just one would (assuming adequate sized intake vents on the front). Whereas 2 fans at the back both drawing air outwards would draw roughly twice the air.
Likewise, 2 side by side but 1 not always running just allows the one that is running to pull air thru the big hole next to it (the other fan) rather than thru the radiator.

Hope that helps

[slidenyo]

unless you consider that there is more possibly more theory at play,
when you pressurise air it heats up, depressurise and it cools down,
create a low pressure zone within the radiator core and the cooling will be more effective as the air will colder.
So for this to happen you retain you factory mech fan and shroud which has to be more effective than the electrical unit and then add a shrouded electric unit for the front.
don't buy an aftermarket one head down to pick a part and get a reputable one from a ford or other euro (normally bosch or gates or the like)
most of the euro cars run two fans which could be beneficially to try match the mechanical as well as allow flow when at 90km/h when fans become ineffective .
the extra shrouding will still restrict flow a little but the negative pressure zone created under the vehicle as it travels will still drag the air through and the cooling should be more effective.

[Mattman]

Don't shroud front mounted fans. If you shroud the front all you will do is restrict airflow.

The shroud works on the back by having the massive frontal area of the radiator available for the smaller area of the rear shrouded fan face to draw air through.

Go and check out manufacturers setups.

Matt.

[slidenyo]

shrouding both sides of the fan will create your low pressure zone across the whole core.
factory setups draw air through or push it through, you will notice that factory push fans are still shrouded onto the edges of the core at the front in a lot of cases with only the pickup area open,
this allows the fan to pressurize the void in front of the rad giving good airflow through the core to the engine side.
a push pull setup should use the same theory shrouds both sides , more pull on the engine side, depressurising air across the whole core

[BigBertha]

wow. alot of good info there,will have to look at getting a shroud for first things, but very usefull information, thanks guys

[4WDbits]

Make sure the viscous fan is working properly, the radiator is clean and in good condition and the factory shrouds are intact and in position.

Additional fans, water wetter etc will help, but a relatively small amount. They are really the icing on the cake, not part of the cake.

There is a lot of mis-information out there, so check the factory setup before spending your hard earned cash.

[Mattman]

That's a great post - factory cooling is usually pretty awesome if it's in good condition so don't spend arseloads converting to something that won't likely be as good.

[BigBertha]

cheers guys, im not having any overheating probs so far just want to reduce the chance of it happening, will look at getting a new shroud first and look at my viscous fan.