Viscous Fan vs 12V Thermo Fans?

[travis2ninja]

HI,
I have a 92 TD27T Terrano, Automatic.
I have done everything humanly possible to prevent overheating.
But yet it still happens on the beach or those hills.
Would it be better to run say twin 10" or 12" thermo fans with a shroud over the standard viscous fan?
Has anyone done this? What difference has it made?
Cheers

[fish]

Way better. If the viscous fan isn't cutting it or is not working properly bring in the big electrics.

[zukmeista]

In my experience (14" thermo vs std fixed fan) the std engine driven fan wins for hard usage, the leccy fan does the job around town and light offroading but if I start giving it shit it heats up pretty quick, rad was recored a couple of months ago so it ain't that. If I had known this would happen I would have stuck with the std fan. If your viscous coupling isn't doing the job just pull it off, drill a holt through it and put a bolt through it, now you have a fixed drive fan with no viscous coupling to worry about.

[CLUMZ1]

Checked your water pump? Is it metal or plastic?

Do you still have a radiator shroud?

Do you still have the side skirts in the wheel wells?

[lax2wlg]

Has anyone done this?
Cheers

Yes, fullthrottle did it with Ford fans and was very happy with the results, search XR6 FANS IN THE TD27 TERRANO or similar. Great writeup there w/ pics and it looks like a factory install too.

[zukmeista]

Yes, fullthrottle did it with Ford fans and was very happy with the results, search XR6 FANS IN THE TD27 TERRANO or similar. Great writeup there w/ pics and it looks like a factory install too.

http://www.offroadexpress.co.nz/Forums/viewtopic.php?f=4&t=34482

[travis2ninja]

Do you still have the side skirts in the wheel wells?

Half have been broken off, Why would it make a difference?

[smurf182]

If your viscous coupling isn't doing the job just pull it off, drill a holt through it and put a bolt through it, now you have a fixed drive fan with no viscous coupling to worry about.

Rangi as, will suck a lot of power from the motor all the time, slow down your warm up time, not to mention dangerous whenever you're working under the bonnet with the motor running.

If your viscous coupling isn't working, fix it. They can be refilled with the correct oil and go for another 20 years.

[tallsam66]

Viscous Fluid is available from BNT comes in 50ml syringes.

[zukmeista]

Rangi as, will suck a lot of power from the motor all the time, slow down your warm up time, not to mention dangerous whenever you're working under the bonnet with the motor running.

My rugger had a fixed drive fan (no viscous coupling) from factory, also most older vehicles had fixed drive fans, so don't see why it would be so bad? Still warmed up quick as, didn't notice a change in power when I changed to electric. Viscous fans still turn when the motor is running too so not seeing your point there.

[CLUMZ1]

Do you still have the side skirts in the wheel wells?

Half have been broken off, Why would it make a difference?

if your inner guard plastics are in good order and you seal up the area from bull bar to bottom radiator support so you effectively reduce the air spill from in front of the radiator and fit some sort of deflector after the radiator then the fan doesn't need to do so much work..

http://www.patrol4x4.com/forum/members- ... dex37.html

[DieselBoy]

In terms of air moving power, in general terms you can rank commonly available fans from worst to best like this:

Electric

Fixed or flex blade engine driven fans

Viscous Fans

Hydraulic fans

Replacing a viscous fan with an electric fan is nuts.

To move as much air as the viscous engine fan you need two 3000 cfm 16 inch fans, shrouded. Big ones. They will draw 21 amps each.
You then need to find another 42 amps worth of alternator to run them.

There is no overall horsepower difference.

Add a electric fan as extra cooling if you feel the need, but your mad if you throw out your viscous.

[slide]

My rugger had a fixed drive fan (no viscous coupling) from factory, also most older vehicles had fixed drive fans, so don't see why it would be so bad? Still warmed up quick as, didn't notice a change in power when I changed to electric. Viscous fans still turn when the motor is running too so not seeing your point there.

There's a big difference between the viscous fan just turning, and when the hub locks in and drives it. The old fixed drive fans are not as efficient, so don't move as much air as a viscous can, but do move more than an uncoupled viscous. Power difference is small, a couple off mm of throttle pedal travel?? Not enough to notice.

[fish]

why would a fixed fan move less air than a viscous?
i thought a fixed fan would be the bigger blower.

i agree tho that keeping it would be better than 100% electric
a combo of viscous and aux would be ideal

[DieselBoy]

why would a fixed fan move less air than a viscous?
i thought a fixed fan would be the bigger blower.

i agree tho that keeping it would be better than 100% electric
a combo of viscous and aux would be ideal

Because a fixed fan is being driven all the time, its design is a compromise between how much air it will push versus how much power it consumes being driven all the time.

That's why viscous fans were developed, you could now have a engine driven fan that had the blade configuration to move HUGE amounts of air, but only when required.

[fish]

so a viscous made fixed would be the biggest mover of air, but perhaps to much so,

is there a way to make my air con fan come on when ever i want? that would be usefull.

[Mattman]

Just identify the aircon fan relay and run a new trigger wire to it from a switch in the dash - easy peasy.

I have done a few electric fan conversions and unless you get a decent high end fan setup like Craig Davies and shroud it properly or use something good from the factory like the Falcon twin fans with shroud then you will end up with less air flow than a stock viscous and you will overheat.

Replace the viscous coupling if you are unsure of it's condition - they aren't that expensive in the scheme of things. Also as has been said fit an after market temp gauge so you can actually get a decent reading. Most stock gauges are crap.

Matt.