Fan Help Please

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Woldsguy

Woldsguy

Active Member
Posts
128
Location
East Yorkshire
Right, I'm back with another newbie query.

Land Rover 90 fitted with 200Tdi

At some point in its history someone has replaced the viscous fan with an electric - looks cheap and cheerful with Japanese writing on it.

The fan operates whenever the ignition is on, even if cold, even if the engine is not turning over. Clearly something not right. So in a break in the weather today I thought I would have a look and see if there was anything obvious.

What I found was: 2 wires coming off the fan, and going into a mass of electrical tape. Coming out of the ball of tape are 3 wires!

2 of these head off towards the dashboard, and the third heads to the injector pump, and from what I can tell (from watching videos about what goes where) connects to the fuel cut off solenoid. Maybe just to the other wire going to it, rather than being operated by the solenoid.

A wild guess here, is that they are using this as a positive, but lord knows why, when there are 2 other wires.

Questions

1) Is this right? -I'm fairly certain I know the answer to this!

2) How should it be wired? By which I mean, I'm guessing one wire should got to a temperature controlled switch, but where? I know some people have a manual switch on the dash, but I'd like to learn how to do it right before I bastardise it.

3) Given the time of year, is it ok to just disconnect the fan for now, and sort it when I have time?

Thanks again in advance.
 
Electric fans should be switched by a relay. I suspect in its current state, the feed to the fuel pump solenoid triggers the relay, which then allows power from the battery to drive the fan.

To me, the optimum setup would be to have the fan powered by its own dedicated circuit directly from the battery, with a relay to switch it on and off. How you trigger the relay is up to you- you could have a manual switch if you wanted to. What is usual is to have a temperature-controlled switch in one of the radiator hoses to switch the relay when the coolant temperature rises. You can use an ignition-switched supply and the fan will be off completely when the ignition is off, or you could use a permanent supply to allow the fan to run after switch-off. Personally I'd use an ignition-switched feed, since this works well enough with the equivalent viscous fan setup.

Edit: Here's the basic idea, though the wire colours aren't correct for a landy
basic-electric-fan.jpg
 
Japanese would normally mean expensive.

Sounds like it's simply wired into a relay. That activates the fan when the ignition is on. Simple but probably fine.

No I wouldn't simply disconnect it.
 
FlyingPete said:
Electric fans should be switched by a relay. I suspect in its current state, the feed to the fuel pump solenoid triggers the relay, which then allows power from the battery to drive the fan.

To me, the optimum setup would be to have the fan powered by its own dedicated circuit directly from the battery, with a relay to switch it on and off. How you trigger the relay is up to you- you could have a manual switch if you wanted to. What is usual is to have a temperature-controlled switch in one of the radiator hoses to switch the relay when the coolant temperature rises. You can use an ignition-switched supply and the fan will be off completely when the ignition is off, or you could use a permanent supply to allow the fan to run after switch-off. Personally I'd use an ignition-switched feed, since this works well enough with the equivalent viscous fan setup.

Edit: Here's the basic idea, though the wire colours aren't correct for a landy
basic-electric-fan.jpg
Click to expand...
Thanks for this. Yes it all makes sense, except following the diagram, the relay should be where all 3 wires meet, I.e. Somewhere in the electrical tape, but there doesn't seem to be anything in there bigger than a wire connector of some sort. How big would a relay be?
 
300bhp/ton said:
Japanese would normally mean expensive.

Sounds like it's simply wired into a relay. That activates the fan when the ignition is on. Simple but probably fine.

No I wouldn't simply disconnect it.
Click to expand...
Thanks for this.

I just read that when they are wired correctly they are hardly ever activated, except when engine is working hard on a hot day. But I'll take your advice and leave it alone.
 
Tdi's tend to run cool. But that doesn't mean they won't kick a fan in. Having it running won't really do any harm, as the t stat won't open until it needs to anyhow. But not having a fan runs the risk of cooking it should it get hot.
 
Using electrical tape as a junction box, plus using the fuel pump feed to have the fan continuously running points to a bit of a bodge job. It will technically work, but who knows whether it's safe. Personally I'd pull the existing fan wiring out and do the job properly from scratch. Alternatively see if you can hook up the proper viscous fan setup instead.
 
FlyingPete said:
Using electrical tape as a junction box, plus using the fuel pump feed to have the fan continuously running points to a bit of a bodge job. It will technically work, but who knows whether it's safe. Personally I'd pull the existing fan wiring out and do the job properly from scratch. Alternatively see if you can hook up the proper viscous fan setup instead.
Click to expand...

This.

You can buy pre-made looms for the fan online from RDX.

Has an override switch, and is temperature activated and works from a fused ignition live supply.

Is all plug and play.
I fitted one and it was a doddle. Hasn't come on once though lol
 
FlyingPete said:
Using electrical tape as a junction box, plus using the fuel pump feed to have the fan continuously running points to a bit of a bodge job. It will technically work, but who knows whether it's safe. Personally I'd pull the existing fan wiring out and do the job properly from scratch. Alternatively see if you can hook up the proper viscous fan setup instead.
Click to expand...
Thanks. Looks like another job for the list.

Why would you recommend the viscous fan over electric? I thought / have read that it drains hp.
 
flat said:
This.

You can buy pre-made looms for the fan online from RDX.

Has an override switch, and is temperature activated and works from a fused ignition live supply.

Is all plug and play.
I fitted one and it was a doddle. Hasn't come on once though lol
Click to expand...
Thanks. Will definitely look into it.
 
Woldsguy said:
Thanks. Looks like another job for the list.

Why would you recommend the viscous fan over electric? I thought / have read that it drains hp.
Click to expand...
Not enough HP for you to worry about! Problem you'd have fitting a viscous fan back in is you've got a 200tdi fitted now (presumably off a Disco), the original cowl ( the tunnel the air is pulled through ) won't fit so you'll have to modify something to make your own. You'll then curse and swear the following week when you'll have to take it all off again to tighten the belts!
If it were me, I'd leave the leccy fan on, but have it temperature switched and wired properly. It won't do any harm unplugging it this time of year, you may even get a few more degrees of 'heat' from the 'heater'!
 
Woldsguy said:
Thanks for this.

I just read that when they are wired correctly they are hardly ever activated, except when engine is working hard on a hot day. But I'll take your advice and leave it alone.
Click to expand...

I had a Kenlowe fan on mine for about five years. For normal driving in France I would probably hear it come on maybe two or three times a year in the height of the summer. On a trip to Morocco crossing the Sahara when the engine was worked hard it would probably come on two or three times a day. I have since reverted back to the Visco's fan which I think I prefer. You don't have to worry about connections etc and wander if it's still working. I originally fitted the Kenlowe as I thought the engine might warm up quicker in the winter and save fuel. It didn't make any difference what so ever.
 
Last edited:
There are pros and cons to both setups.

Tdi's can need a fan, using them off road properly, even in winter it's fairly easy to get the fan to kick in. And if you are modified running higher EGT's, then certain use will make the engine run hotter too.

If you want to put a nice thermo switch in. Get one of the X-fan switches:
http://foundry4x4.co.uk/index.php?route=product/category&path=65_1760

I suspect it wouldn't take much to wire it in with the bits you already have. I agree, it does sound a little bodgy at present, but fundamentally if it's wired how it sounds it is, then it'd actually probably ok.

I don't know if you know what a relay does. In this instance it's just a remote switch. It sounds like the fan is connected directly to the battery (assuming that the wires heading for the dash make it all the way to the battery or fuse box).

This means all the current goes through these wires. The person who fitted it wanted the fan to come on when you turn the ignition on. So the feed from the injector pump only gets live with the ignition. This simply sends a signal to the relay to say "switch on".

They could have fitted a manual switch instead, allowing the driver to turn it on and off. This has benefits that it doesn't run all the time, but the downside that you need to manually monitor temps to turn it on and off.

Adding in a thermo switch would have been more money, although they are pretty cheap. But some electric fan kits make it all look very expensive.
 
Woldsguy said:
Why would you recommend the viscous fan over electric? I thought / have read that it drains hp.
Click to expand...

All fans will use power while they're running. With an engine-driven fan, it's directly off the crank pulley. With an electric fan, it's through the increased current draw on the alternator. All energy is ultimately traced back to the crankshaft.

Compared to a fixed (non-viscous) fan, an electric one may offer a slight saving. However, tests are often skewed by running a stationary bench test, while in real life, air flow through the radiator caused by the vehicle motion will reduce the load on a fixed-blade fan. In the real world the results will be more similar. A viscous fan counters the drawback of a fixed fan with its ability to reduce its drive torque. once you're underway it's essentially off- the air being blown through the radiator due to road speed will 'unload' the fan sufficiently. At idle or during low-speed work, the fan will draw sufficient air through the radiator to cool the engine.

The real reason electric fans are so popular on modern vehicles is that the majority have a transverse engine. In practical terms, you can't have an engine-driven fan in this case and electric is therefore the only option.

The main advantage of a viscous fan is that they're very simple. They fit to the coolant pump pulley, so the drive mechanism is there anyway. Control is through the viscous clutch which is entirely self-contained in the fan assembly. There's no wiring, no relays and no switches to fail. If the viscous coupling does fail, it's usually possible to make a temporary fix (to lock the viscous clutch) which will get you home. If an electric fan fails, there's no fan.
 
Woldsguy said:
Right, I'm back with another newbie query.

Land Rover 90 fitted with 200Tdi

At some point in its history someone has replaced the viscous fan with an electric -
Click to expand...

It would probably be better to go back to viscous fan and cowl. It is what the designer intended, and what I have seen in practice to be better a number of times.
May be OK to run a Tdi for a bit without, but better to have the backup cooling capacity if needed.
 
300bhp/ton said:
I don't know if you know what a relay does. In this instance it's just a remote switch. It sounds like the fan is connected directly to the battery (assuming that the wires heading for the dash make it all the way to the battery or fuse box).

This means all the current goes through these wires. The person who fitted it wanted the fan to come on when you turn the ignition on. So the feed from the injector pump only gets live with the ignition. This simply sends a signal to the relay to say "switch on".

They could have fitted a manual switch instead, allowing the driver to turn it on and off. This has benefits that it doesn't run all the time, but the downside that you need to manually monitor temps to turn it on and off.

Adding in a thermo switch would have been more money, although they are pretty cheap. But some electric fan kits make it all look very expensive.
Click to expand...

I thought I did. But obviously I'm being a bit dim. (Not helped by a trip to the pub last night). I think I'll take a pencil and paper and draw it out while look g at the fan. (I thought the relay would still have to physically be positioned where the 2 wires became 3, and I can't see one there).

Thanks for taking the time to explain, I will sort it. Probably add a thermo switch, (I do understand basic plumbing!!)
 
Thanks FlyingPete and Turboman, looks like I have a two stage job.

1. Check and secure what's already there, and add a thermo switch if not too expensive

2. Longer term, look to refit a viscous fan, I agree Turboman, I like to have things as they were designed to be. (Unless, of course, it's a known design flaw)
 
Woldsguy said:
Thanks FlyingPete and Turboman, looks like I have a two stage job.

1. Check and secure what's already there, and add a thermo switch if not too expensive

2. Longer term, look to refit a viscous fan, I agree Turboman, I like to have things as they were designed to be. (Unless, of course, it's a known design flaw)
Click to expand...
Viscous fans work well, occasionally the coupling go, but dirt cheap and easy to fix. Another benefit is the cowl stops so much water and mud splashing up into engine bay.
When I took the Kenlowes off mine, I got a fan and a cowl from a breaker for 50 quid.
 
I can't really fault a Kenlowe fan, mine did its job, it was linked to a temperature sender which tripped it in and out automatically. It gave more room to work in the engine bay without the cowling being there. But I always found myself checking the temperature gauge and wandering if it was still working. With the Visco's fan, you just forget about it. The temperature gauge just stays the same no matter what your doing. I also like to keep things as standard as possible. I have a Visco's fan on my Sprinter van which now has six hundred thousand on the clock. Never had a problem. I know Mercedes Visco's is not a Land Rover one but at about £30 for a viscos fan from Paddocks they are cheap to replace. And easy if you have the special spanner. I have had a couple of electric fans fail on me in various cars I have had, but not had a visco's one fail yet. When the Defender starts up yes it does turn the fan over until it has warmed up, then its just ticking over until needed. Visco's for me, no contest.
 
Hi
This has nothing to do with your question but I too have a 90 with a 200 tdi engine conversion. It's a 1987 and I bought it a couple of weeks ago. Thought I would say hello and maybe we could exchange notes on stuff if you like?

I tried to work out how to pm on this site but couldn't see how to do it.
 
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