Electric fan switch

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cowasaki

cowasaki

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I have a selection of decent quality large electric fans including one off a SAAB which virtually fits the defender as if it were designed for it. So I'm thinking of going electric. I can wire a manual switch up but I was looking at temp controlled switches and saw these on ebay:

RADIATOR FAN SWITCH FOR LAND ROVER DISCOVERY 2.5 1989-1998 VE709019 | eBay

or this one: http://www.ebay.co.uk/itm/Quinton-H...arts_Vehicles_CarParts_SM&hash=item53fc541a98


Does anyone know if there is an easy spot, preferably an already tapped hole, that one of these will fit into. If I can get one of these in then the total cost of going electric will be under £20


EDIT: That this one is helpful in giving specs.... http://www.ebay.co.uk/itm/Facet-Ele...arts_Vehicles_CarParts_SM&hash=item2a2ff8b122


EDIT2: This one (PRC3541) has same spec as one above (EDIT) but different temperature range: http://www.ebay.co.uk/itm/DEFENDER-...arts_Vehicles_CarParts_SM&hash=item3cc91cdbdc


EDIT3: What temperature should I ideally want the fan to come on at ?
 
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As above, the X-Eng adaptor is the best bet although I replaced the supplied switch with one of a different rating.
Ensure you fit it in the bottom hose as it is designed to operate the fan only if the natural through-flow of air through the rad is not sufficient (which is usually is).

I also have a manual over-ride for OFF & ON. OFF for wading etc and ON to give the fan a spin from time to time.
 
There are a couple of locations that look like they might take the standard M22x1.5 threaded fan switch...... My thermostat cover has what looks like a plastic bolt in it. It appears to be about the right size so I think I will check that first because if it is then it will make the installation far more tidy and straightforward.
 
This is the thermostat cover. Hoping that the thread of the part listed as ERR4686 "Plug coolant filler" is M22x1.5 and could take a standard thermostat. It would be so much neater than cutting pipes and inserting assemblies costing about £35-40 in order to get the same benefit.

300tdithermo.png


If anyone knows what the thread size and pitch is it would be helpful if not I will attack it tomorrow and check.
 
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Don't know the thread off-hand but if you go down that route you will be measuring coolant temperature not only before it reaches the radiator but even before it has left the thermostat housing. In no way, shape or form will you be taking into account the cooling effect of the radiator or if additional cooling (i.e. the fan) is even required.
 
Litch said:
Don't know the thread off-hand but if you go down that route you will be measuring coolant temperature not only before it reaches the radiator but even before it has left the thermostat housing. In no way, shape or form will you be taking into account the cooling effect of the radiator or if additional cooling (i.e. the fan) is even required.
Click to expand...

Is that not where you want to measure it? That is where the temperature gauge sender is located. i.e. measure the temperature and then decide IF it needs the addition of the fan.

Just asking, I'm not saying I'm right.
 
No.

The radiator fan is only used to provide additional cooling if the radiator is not providing sufficient cooling itself (stationary / slow moving driving, heavy towing etc). 99% of the time the fan is not required however for the 1% when the radiator can't provide sufficient cooling itself the fan provides an additional flow of cooling air to bring the temperature down.
LR's have always been known for being over-cooled owing to the diverse nature of operating conditions they are designed to be used in so in more temperate climates (like the UK) some people remove the fan completely and rely purely on the normal cooling effect of the radiator. Now I for one would NEVER do this, what price a boiled engine & warped head in a traffic jam on a hot day?
 
But if the radiator wasn't supplying enough cooling wouldn't the core temp start to rise i.e. the gauge and therefore the switch would go on.... again, I'm just asking to find out.

I actually have a Kenrow temperature bulb thing somewhere which I suppose I could use!
 
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OP, when the engine is cold, the wax stat in the thermostat housing will be closed, so that the engine heats to operating temp as quickly as possible.

Once operating temp is reached, the wax stat opens, and the radiator joins the cooling circuit. This will provide sufficient cooling as long as there is good air flow through the rad. The wax stat will open and close as necessary to allow or restrict water flow through the radiator.

When all is well, you will find that the bottom hose does not get very hot. When there is no air flow the rad is unable to dissipate all the heat and the bottom hose temp will start to rise. This indicates that the rad cannot cope and needs help in the form of airflow from the fan.

That's why the bottom hose is the best place for the fan stat - hope that makes sense. Depending on how you wire your fan, it's also a good opportunity to alert the driver that the engine is getting hot, so that you can monitor it carefully and ensure that the fan is doing it's job.

In my case, the fan is permanently live, so it will continue to run with the engine hot if turned off. I also have an override switch so that I can force the fan on. The switch has a tell tale led which illuminates whenever the fan is on.

In the unlikely event that I'm wading, I can remove the fuse. It's a good idea to wire via a relay to save your switch from burning out as the current draw from a fan is quite large.
 
That explanation makes sense, the electrics is my bit to be honest. I was going to have a 3 way switch with an RGB LED. I can make it green until it reaches the temp then red or yellow if at temp and switched on or blue if at temp and on auto. Switch can be off/auto/on.

I might have a play using a temp sender and you could adjust the temperature of the switch on using an LCD and adjust whether it operates with ignition or live. The LCD would act at a post radiator temperature gauge too.
 
MR BFG said:
I have one of those kenlowe thermostat switch adjustable things of your interested?

Same as this: Kenlowe Thermo Switching Sensor at www.rimmerbros.co.uk
Click to expand...

Thanks for that but I actually have one too (see post #9)..... The idea of the on/off thermo switch was neatness. I really don't like the Kenlowe jobby to be honest. I will have a bit of a play...... I can do this whilst the standard fan is in place until I am happy with it.
 
You can fit on the hot hose if you want, but it's not going to be as accurate as the cool side or work as effectively. It also means your engine is starting to overheat before you start to deal with the problem. Having it on the hot side, is more of a preventative measure and makes more sense to me as you are only going to intervene when natural cooling cannot take place.

Don't be fooled by style over substance. Overheating causes a lot of expensive damage quickly. Personally I would have preferred to have the original viscous fan in place, but that was not an option for me as I did not have a cowling. I do like the extra space in the engine compartment with the electric fan though!

Also, fitting on the bottom hose meant I could reuse my old NA bottom hose in the conversion as it was a perfect fit once it was cut and rotated!
 
sp00k said:
........Personally I would have preferred to have the original viscous fan in place, but that was not an option for me as I did not have a cowling.....
Click to expand...

I've not yet got my defender on the road yet (barely had time to touch it..) but an electric fan is on the list so I'm intrigued as to your thoughts..?

I'm expecting it to make a significant difference to mpg in winter months - but I might be wrong?

Tom
 
I took the Viscous Fan off mine (200tdi) over a year ago. My intention was to replace with an electric one down the line sometime. Gauge never moves once up to temp, even when towing, with no fan. Just a thought:D
 
LRD90tdi said:
I've not yet got my defender on the road yet (barely had time to touch it..) but an electric fan is on the list so I'm intrigued as to your thoughts..?

I'm expecting it to make a significant difference to mpg in winter months - but I might be wrong?

Tom
Click to expand...

Check that your stat is working properly - if your mpg is bad and your engine is slow to warm, it may be stuck open.

If the viscous is working properly, then when the engine is cold, it should hadly be turning (the test is being able to stop the fan with a newspaper or similar).

When the engine is hot, the viscous fan should be locked. It's blades are huge - much deeper than an electric and with the cowling it moves a lot of air through the radiator, so it should be much more efficient than an electric fan.

Also, the viscous is simple. It only has the viscous link itself to go wrong, and if it breaks you could always stick a screw or similar thorough it to lock and and force it to turn.

The electric is much more complicated. There is the fan, sensor, relay, switch and wiring, all of which can fail.
 
sp00k said:
Check that your stat is working properly - if your mpg is bad and your engine is slow to warm, it may be stuck open.

If the viscous is working properly, then when the engine is cold, it should hadly be turning (the test is being able to stop the fan with a newspaper or similar).

When the engine is hot, the viscous fan should be locked. It's blades are huge - much deeper than an electric and with the cowling it moves a lot of air through the radiator, so it should be much more efficient than an electric fan.

Also, the viscous is simple. It only has the viscous link itself to go wrong, and if it breaks you could always stick a screw or similar thorough it to lock and and force it to turn.

The electric is much more complicated. There is the fan, sensor, relay, switch and wiring, all of which can fail.
Click to expand...

Great explanation - thank you! :)

I'll check next time I with her and there is juice in her battery!

Cheers
Tom
 
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