Last updated:  2004.08.09

 ©  Text and Photo: Frode H. Haaland

 

New Electric Fan

Vehicle: Land Rover Discovery 1990 200tdi

 

The old viscous fan died a month ago, but an electric fan from a car breaker resided way back in the garage. The modification was well overdue as its thermostat was purchased more than two years ago. It turned out to be a very easy job!

 

The old viscous fan
Viscous fans tends to loose their fluid over time, making them work fulltime. This is diagnosed trying to turn the fan while engine is cold. If it doesn't spin freely, the fan is knackered. If it doesn't stiffen up while engine is very hot, it is also knackered.

My fan had a breakdown in its bearing - seen as the fan didn't spin circularly, it was not true... Removal showed balls from its bearings lying freely in its hub... Time to call in the spanners!

 

New, electric fan
Purchasing a dedicated, proprietary fan from Pacet, Kenlowe, Famous Four or others, is of course the simple solution. They come with waterproofed engines, all its fittings, and it is for sure they will fit your engine.

But I opted for the cheaper variety of pulling a fan from a car at a breakers yard, and purchasing a thermostatic relay to run it. Most fans are made from Nippondenso, Valeo or similar, they look very similar - and their sized are all but the same.

I do not know anymore which car it came from, but as a Nippondenso it must be a jap. The thing to make sure is it will fit in front of the engine/rear of radiator. The waterpump spindle is the difficult spot to clear.

So a pulling fan is what's needed. A blower fan can also be used, but the space in front of the radiator is dedicated for a bigger intercooler also from a breaker, so a puller was the choice of mine (a Citroen XM has a double blower that fits nicely in front of radiator).

 

Thermostat
One of the main points in using an electric fan, is that as a fan is not needed most of the time, so you save some fuel running without a fan. In fact, for most of its 15 years, Otto has been running without the viscous fan at all! In norwegian climate, it seems to be needed only when offroading, when there is no breeze of air through the radiator.

An electric fan should start when needed, and stop when not needed - so needs a temperature sensor. This sensor starts the fan at a given/set temperature, and stops when the engine is cooler again. 

As temperature builds up after switching the engine off/not running, the fan should be installed hot-wired, so it runs regardsless of engine/ignition. This way, it will sometimes run after you have parked the engine. Keep this in mind when working in engine compartment!!!

An adjustable capillary thermostat were sourced from RS-Components; RS-Components part# 561-460 , made by Altecnic (part#556501 in manufacturers system),  0-120º Celsius. It  looks exactly like what Kenlowe use, but cost £12.50 and not £40 as Kenlowes... It features a probe/sensor being plumbed into top radiator hose  This allows you to adjust the temperature which will ignite the relay and make the fan/s start blowing.

The fan should be installed using a two- or three-point switch:

1) Normal: Automatic, thermostatically controlled

2) Off: No current to the fan whatever temperature (used when wading)

A third option might also be used: 

3) On: Fan blowing all the time
The sensor is plumbed into the top radiator hose, using two hoseclamps to try to reach a tight connection. I had to tighten the clamps very hard to get a good seal; try fitting the clamps on the opposite side of the sensors copperline to ensure a better sealing.

 

Fitting the fan
The fan has to be placed close to the oilcooler to clear the protruding waterpump spindle.

One of the fitting holes were perfect for one of the bolts coming from the radiator top panel. This was then made the starting point. The next top-hole were marked up and drilled through the top panel, and a bolt was fitted. Now the fan hangs securely on top, but has no fitting below.

Two small pieces of iron made up the lower securing points. The end of the brackets just slotted into the recess under and behind the radiator (where the radiator rests), and a hole drilled through the bracket to take the fitting bolts. So the lower mounting points are really just "resting points"; as soon as the top nuts are removed, the fan can be lifted out. Much like the radiator itself.

The fan should be placed with its electrical coupling facing downwards, but when marking up for drilling I had put it the wrong way around - only to be recognized when everything was fixed. So turning the lot around, drilling new holes etc would have to wait for another time...

The two top mounting bolts arrowed.

 

The electrics
Fan end

When the fan was cut loose from its car at the breakers yard, the wires were cut so that the connectors are still in place. This makes removal of the fan much easier. This is to be wired through a thermostatic relay, that will be plumbed into the top cooling hose.
Thermostat-end

The thermostat found its place after a bit of searching. Adjacent the intercooler/PAS-bowl seemed to be a nice spot: The thermostat-sensor-wire will have a short and easy routing, the thermostat will be on a pretty protected spot, and there were a large hole for the thermostat knob spindle already.

The thermostat were set at ~95º
Supply end

The relay needs a hot-wiring, meaning it should have current regardless of ignition. A high-amp oulet were set up under the radiator overflow bowl, also supplying the headlamps. The battery connection is in fact 35mm2, and the item is intended for hi-amp car stereos. With this outlet in situ, almost any ampdrawing device can be fitted. Don't forget an inline fuse though!
The setup was made very easy as time was running out for vacation, but later it should receive a switch enabling running all the time, all turned off (for wading), and the standard thermostatic control. This will have to wait for another day...

 

Finished result
During the installation, I checked it worked by turning the thermostat down to around 20° Centigrade. To check if the setup actually worked when engine gets hot, I had to adjust the thermostat to slightly above 90° - and it starting blowing after a motorway blast.

Job well done (that is: I will have to make new brackets and drill for new top mounting bolts to turn the fan round the correct way to ensure a better water sealing...)