Offroad-Express

Been looking into replacing the viscous fan on my LN61, 2Lt with a large electric one. Now from looking around, quite a few people say don't do it, they don't provide enough airflow. This I assume is to some people maybe buying a $50, 10", special from Repco?
I have a 600w, 18" fan from a BMW X5 3.0 turbo diesel 6. Flow is about 3500cfm. I would think this would be big enough to keep the 2L cool under any load it might be put under, considering it keeps a 170kw turbo 6 in a 2200kg truck with 2800kg trailer cool?
Any thoughts?

Rollux wrote:Been looking into replacing the viscous fan on my LN61, 2Lt with a large electric one. Now from looking around, quite a few people say don't do it, they don't provide enough airflow. This I assume is to some people maybe buying a $50, 10", special from Repco?
I have a 600w, 18" fan from a BMW X5 3.0 turbo diesel 6. Flow is about 3500cfm. I would think this would be big enough to keep the 2L cool under any load it might be put under, considering it keeps a 170kw turbo 6 in a 2200kg truck with 2800kg trailer cool?
Any thoughts?

i have both if you can put the eletric fan infront of the radiator (mines on a switch and i turn it on when off road as theres not as much airflow as driving on the road) and i have the viscous fan off the engine.....DO NOT DITCH YOUR VISCOUS FAN!!!!! reason being is if you drive in alot of mud and mainly water those fans car get water in them or in the wiring and you can fry them being left stranded with a eletcic fan that dont go isnt very useful where as if it fails you still have the viscous

my $0.00002c worth

You're supposed to turn them off when you go through deep water

turoa wrote:You're supposed to turn them off when you go through deep water

ohhhhh............. lol

Was looking at me std fan in the LN 60/1 any risk of that ploughing the radiator? Gap looks to big for it to reach.

Not looking at using this truck in that much mud or water. Mainly use it on road and for getting to my fav camping grounds, like a riverbed, forest park etc. Was wanting to ditch the viscous to gain a bit of extra power.

Rollux wrote:Was wanting to ditch the viscous to gain a bit of extra power.

The viscous fan only works when the coolant is hot enough to cause the heat sensitive spring to activate the viscous fan.
It also runs at low speeds whn there isnt much airflow coming through the radiator.

The electric fan will increase the resistance in your alternator and also suck the power from your engine.

It takes an equal amount of horsepower to run a fan regardless of whether its electrical or viscous

No such thing as a free lunch.

If the viscous fan isn't performing then you might need to replace the clutch assembly.

Generally speaking a viscous fan will flow more air than an electric fan unless you have the electric shrouded.

The electric fan offers manual control which can be useful. The fan can be off, auto, or on with some simple wiring. Allows water crossings with the fan off or extended running of the fan if required.

Most likely the viscous fan will be worn and not be working correctly. Some units allow the replacement of the fluid in them but usually the entire unit is replaced.

Matt.

I replaced the viscous fan in my 3.0l V6 surf after it was damaged in a couple of very deep river crossings. I spent about $220 on either a 16 or 18 inch fan from repco (cant remeber which but it covers almost the entire width of the radiator).

I havent had any problems with cooling with this fan since i installed it - it is very powerful i have it mounted behind the radiator sucking cold air through the radiator and can feel it sucking the air in from well in front of the grill on the truck.

I have a switch in the cab so that i can turn it on and off when im going through deep water and touch wood havent had any problem with it and its been on for about 18 months now. Definitley no noticeable increase in power or full consumption though which is unfortunate driving this thirsty girl

Sorry about the hijack. But does anyone know of a reliable method for working out whether your viscous fan is doing the business or not?

roscoFJ73 wrote:

Rollux wrote:Was wanting to ditch the viscous to gain a bit of extra power.

It takes an equal amount of horsepower to run a fan regardless of whether its electrical or viscous

No, it doesn't. Electric motors are much more efficient than a viscous clutch that loses a lot of power to friction/heat. Why do autos put less power to the ground than an equivalent manual trans? Power loss through heat generated by the torque converter, which works on the same principle as a viscous fan clutch. Also with less reciprocating mass bolted (ie. inertia) to the crank removing your viscous fan will be like lightening your flywheel.

My fan is working fine, but from past experience (with V8's at least), ditching the fan for electric makes a noticeable improvement - freer revving, smoother idle and a small improvment in power and economy.

Also, the fan locks up when cold until some warmth reaches it, and also it is always robbing some power when at normal temp, about as much as an A/C compressor does. If you can't notice the diff between a/c on and off, you prob won't notice removing the fan.