Anderzander Posted June 9, 2022 Share Posted June 9, 2022 I’m going to fit an electric fan to the 200tdi my 80”. Some of the long steep climbs on hot days on the lanes in Yorkshire showed up that a fan-less cooling system couldn’t cope. I’m a complete ignoramus on electric fans though - so any advice offered would be more than welcomed. There is no space behind the radiator - so I’m going to measure up and fit a push one on the front. My questions are on how to control it and wire it. Control Switch There is no space in the bottom hose to put the usual insert with a sender, and the sender spot in the thermostat has a capillary gauge into it. Someone suggested either a capillary tube into the bypass pipe I put across the head where the heater pipes were. I had another suggestion to use one that reads the surface temperate - they had a sensor from a tiny strip that slid between the radiator fins … which I can’t seem to see for sale anywhere ? Closest I could find was this : https://www.carbuilder.com/uk/surface-mount-fan-switch-100c82c Any suggestions or recommendations from anyone ? The only other options I could see would be drilling and tapping the blank on the front of the 200 thermostat- or somehow soldering a fitting onto the copper pipe I have where the heater was? I’m not really sure how viable either of those would be. Wiring. On the wiring front - the 80” isn’t exactly full of wiring. There are almost no relays on the car, with just direct switched loads. It would seem a decent spot for a feed on a fan (which I think are pretty power hungry) would be one straight from the alternator. Is there a fan switch out there that can handle the full load - or so they all need a relay. Probably sounds daft - but it would be nice to keep the wiring as simple as possible. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 9, 2022 Share Posted June 9, 2022 You could drill and tap the bottom of the radiator, and screw the same switch in that the x-eng doohickey uses. If it is still a brass rad, then you could something soldered in quite easily. You want to avoid putting stuff on the engine or in the top hose if you can, wrong place to measure it for switching the fan. The normal intermotor switches can handle 20A if I remember right, so will run a single medium size fan, but a relay will help, and allow you to more easily wire in a manual switch if you wanted. Quote Link to comment Share on other sites More sharing options...
Jon W Posted June 10, 2022 Share Posted June 10, 2022 In my V8 series I used a Davies Craig electronic fan controller which allows you to adjust the temperature that the fan kicks in. I was finding it was getting too hot with the x-eng thermostat temperatures even when i used the lower stats i could find. This allows me to adjust it to come on sooner if i am off road and heat is starting to build. I can also see the temp of water existing the rad on the display. This uses a bottom hose connector though so it won't help your locating problem. For a Tdi standard temp senders/stats should be ok as seem fine on my defender I mounted fan in front of rad by used of simple metal angle iron and mounted a spal push fan. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted June 10, 2022 Share Posted June 10, 2022 I drilled and tapped the thermostat housing for my temperature switch. My fan comes on a bit earlier than it really needs to but I'd rather have early. Wiring is as you would spotlights, use the temp switch in place of main beam. You can add a manual/over ride switch but I didn't bother. I took the switch feed off ignition stage one so it can't flatten the battery but you may need to sit and wait while the temperature comes back down. Mike Quote Link to comment Share on other sites More sharing options...
smallfry Posted June 10, 2022 Share Posted June 10, 2022 Another vote for drilling and tapping thermostat housing. I know nowadays it is the convention to go for somewhere on the cold side of the cooling system, but that is because most modern systems are running on the ragged edge of only just enough capacity in both quantity of coolant and radiator size, plus its good for emissions (but we dont care about that) and many modern engines are quite fragile regarding their cooling. I would always run a relay, and I would use the little 70 amp Durite ones, as I think more is always better ! Ignition controlled though, I dont see the point in the fan "running on" as a lot of modern vehicles do, then the engine has been shut off and coolant is not being circulated. Only benefit is cooling the engine bay as far as I can see. You should be letting the engine idle for a while prior to shutting down, if it has been running hot/working hard in any case ! Sorry, direct from "Sucking eggs, a guide for Grandmothers" I always prefer the push or blow through format, to me it seems much more effective quickly. However, there is the opinion by some that it actually inhibits cooling, but I never found it a problem. 1 Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted June 10, 2022 Share Posted June 10, 2022 As I refuse to use Aluminium and plastic radiators, when I get my brass and copper ones rebuilt, I have a standard european femal fitting for a sender fitted in the lower lhs corner (opposite the return pipe. This then gives me a clue as to how effective the rad is. If I was to fit an electric fan, I would fit the sender here Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted June 10, 2022 Share Posted June 10, 2022 Don't fit one In all seriousness I know you don't have the space so it's your only option but every vehicle I've driven with just an electric fan has had problems. Viscous or hydraulic and electric not an issue, viscous or hydraulic on their own not an issue. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 10, 2022 Author Share Posted June 10, 2022 Great input - thank you 16 hours ago, Bowie69 said: You could drill and tap the bottom of the radiator, and screw the same switch in that the x-eng doohickey uses I should have thought on it before I had the recent work done on the radiator. It does have a drain fitting on it - 1/8” BSP and even with an adaptor I’m not sure I could make it work to fit a sender on it. 🤔 8 hours ago, Jon W said: In my V8 series I used a Davies Craig electronic fan controller I looked at those - they say you can fit the sender in between the fins on the radiator, which would definitely be the easiest route. https://www.t7design.co.uk/davies-craig-digital-thermatic-fan-ewp-controller-5mm-probe-12v-0444.html Not sure how I could get it to blend in with the 50’s look or hide it though .. 8 hours ago, miketomcat said: I drilled and tapped the thermostat housing for my temperature switch. What’s tricky for me is that I’m using the series housing top .. so the bit ai have to drill and tap is small … 5 hours ago, Nonimouse said: my brass and copper ones rebuilt, I have a standard european femal fitting for a sender fitted in the lower lhs corner I could take the radiator out of mine again and get a fitting soldered on. Would you recommend any fittings ? 5 hours ago, Ed Poore said: Don't fit one 😱 Perhaps the saving grace is that it’s only become an issue when I’m off road at very slow speeds - no airflow and hot days. Any other circumstance and the needle never moves from 82° to 88° Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 10, 2022 Share Posted June 10, 2022 Just have it manually switched? 1 Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted June 10, 2022 Share Posted June 10, 2022 32 minutes ago, Bowie69 said: Just have it manually switched? That's how I run mine, only ever needed when off-road regards Stephen Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 10, 2022 Author Share Posted June 10, 2022 I thought about that - but I wanted the safety net of it catching the temp increase before I did … I’m often distracted on bumpy ground. 1 Quote Link to comment Share on other sites More sharing options...
Daan Posted June 10, 2022 Share Posted June 10, 2022 Did you try a series 3 rad? Quote Link to comment Share on other sites More sharing options...
muddy Posted June 10, 2022 Share Posted June 10, 2022 Just fit a T on the gauge sender. Spal fans are decent, having a look round a scrapyard is usually the best way as you can get a few spares. 1 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 10, 2022 Author Share Posted June 10, 2022 49 minutes ago, Daan said: Did you try a series 3 rad? No ! … I love the original rad too much Quote Link to comment Share on other sites More sharing options...
miketomcat Posted June 10, 2022 Share Posted June 10, 2022 Fit the x-eng tube and switch in the top hose? Or just use a manual switch. Our 110 has manual switch the ibex has automatic switch. Both work well just one requires driver input. Mike Quote Link to comment Share on other sites More sharing options...
Escape Posted June 11, 2022 Share Posted June 11, 2022 My 2 cents: - an engine driven fan can (will) be more powerful, so if possible is my preferred choice. But sometimes you don't have the choice, like in your case or in a mid-engined car with the rad up front. Pulling fans have an advantage as it's easier to design a cowling that allows air to pass over the entire radiator and then through the fan, also when not engaged. You can even add flaps to the cowling that open to provide an easy pad to the airflow when moving. Pushing fans only really affect the area directly behind. - location of the control switch is often discussed. It is true you want the fan to come on to increase airflow when the radiator temperature rises. So logically the control switch should be at the outlet. But the ultimate goal is to control engine temperature, working together with the thermostat controlling the coolant flow. So it makes sense to have the control switch near the inlet of the radiator for a more direct reading of the engine temperature. If all is working as it should, there shouldn't be any noticeable difference. If something is going wrong with the cooling system, I'd be more at ease knowing the fan comes on in relation to engine temperature rather than radiator temperature. As an aside, wouldn't it make sense to have the control switch activate at lower temperature if located at the radiator outlet? I know some switches can be set for different temperatures, but most are fixed. - always add a manual switch. It's very easy and gives you a bit more control. For example when you have some traffic just before reaching your destination or a slow offroad section before a stop. Rather than have the fan come on automatically just when you arrive, you can switch it on a bit earlier and get the temperature down before you turn off the engine. Or just as a backup should the control switch fail. Filip Quote Link to comment Share on other sites More sharing options...
simonr Posted June 11, 2022 Share Posted June 11, 2022 For what it's worth....I agree, an engine driven fan is way better (about 10kW of cooling, compared to 1kW) - however, it's not always possible. For an electric fan, the sensor should go on the radiator outlet. Why? Two reasons - it's a no-brainer that the water going in is too hot. If it wasn't, you wouldn't need a radiator! Fitting in the bottom / outlet tells you how good a job the radiator is doing on it's own. If it's not enough, the fan comes on. Second reason is, when you are low on coolant, a sensor at the top of the engine will likely not be in contact with the water - and may stop the fan when it's most needed. On Land Rovers, people started fitting them in the top hose because it's easy, not because it's ideal. It's so common, now people think this is where it ought to go! If you want an adjustable, no-drill solution, get a thermostat from a tea-urn. They have a capillary which you can push inbetween the radiator fins & secure in place (preferably with heat transfer compound). They are usually adjustable from about 30 to 110C - so you can decide how much cooling you want / need. https://www.ebay.co.uk/itm/223968227395 4 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 11, 2022 Author Share Posted June 11, 2022 1 hour ago, simonr said: If you want an adjustable, no-drill solution, get a thermostat from a tea-urn. They have a capillary which you can push inbetween the radiator fins & secure in place (preferably with heat transfer compound). They are usually adjustable from about 30 to 110C - so you can decide how much cooling you want / need. https://www.ebay.co.uk/itm/223968227395 Genius !!! Just for the record - my preference would always be mechanical ! I mean this car has a mechanical clutch actuation - No hydraulics….. just no space. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 11, 2022 Share Posted June 11, 2022 PTO off the front of the crank, cush drive, through the hole in chassis crossmember, bearing carrier, pulley on end of shaft, belt up to second, fan pulley supported in second bearing block, which has centrifugal clutch and fan attached. Purely mechanical.... simpler than electric? 🤔 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 11, 2022 Share Posted June 11, 2022 I'm not entirely joking, perhaps could work, if you have space? A simplified variation of course. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 11, 2022 Author Share Posted June 11, 2022 To give me best clearance over the axle my front sits a bit higher than the front PTO hole in the crossmember. I don’t mind going electric on the front - it’ seems the most sensible way to address my slow speed hot running. Just wanting the tidiest, most effective, way of switching it. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 11, 2022 Share Posted June 11, 2022 Cool, I expect @simonr already has it fully sketch out 😉 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted June 11, 2022 Author Share Posted June 11, 2022 I’ve ordered one of these: 1 Quote Link to comment Share on other sites More sharing options...
steve b Posted June 12, 2022 Share Posted June 12, 2022 Are you going to use a push fan from a standard car type application ? They are generally much more powerful than aftermarket add-on's , and often very compact. Steve 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 12, 2022 Share Posted June 12, 2022 32 minutes ago, steve b said: Are you going to use a push fan from a standard car type application ? They are generally much more powerful than aftermarket add-on's , and often very compact. Steve Much cheaper and could be more reliable as they would have large warranty impacts for manufacturers while after market fan warranty claims would be limited to the price of the fan. Quote Link to comment Share on other sites More sharing options...
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