Guest AKATheWolfman Posted July 4, 2007 Share Posted July 4, 2007 Ok so I've had the car since wednesday last week but I only got my insurance documents this morning (so I couldn't get my tax ntil today). I already knew that I had a leak, which was an upset, but now that I'm using the car I have realised a more pressing problem. My cooling fan on the radiator isn't working! Ok so the guy sold me a car that has a few problems on it. I paid £650 which I thought was a fair price. I'm just hoping that nothing more goes wrong with it since I already had to wire in a new stereo after the guy before the guy who sold it to me totally butchered the wiring when he took his out. Anyway on to my problem: Basically I was sat there on the drive after I got home from work and noticed that the car runs pretty cool. So I sat there and watched the temperature rise. And rise it did. Right the way up to the red. With the needle just about to enter the "danger zone" I thought better of my little experiment and cut the engine. On which I was congratulated with a dribble of water escaping from the header tank and the pipes where they join the radiator at the bottom. In short, not impressed. Especially since the guy told me that it never overheated while he had it and that everything was in order. So I'm just crossing my fingers that he hasn't lied about anything else. I've read THIS thread on the cooling system and I just popped outside to have a look at what I can see on my car. It looks kinda different to what was described in the other thread, but that is for a later model. Mine's an '85 Mk3 1.6i cab. I can see things that look like the objects described in the thread, but the wires are different colours (I think, as they are pretty old and discoloured) But the wires from the temp sensor appear to be red/black and brown and are quite hefty, suggesting that it carries the operating current for the fan. The fan wires seem to be brown/black and brown? I'm not too sure as it's dark out there right now too lol! I can see the really thin cable that goes presumable to the temp dial (which is reading correctly by the way). But the fan doesn't come in. So I had a bash and shorted out the sensor I described above. It's located high up on the engine in what appears to be an aluminium cast where the water pipes go to the head. It didn't make the fan come in either. So I checked the fuses. They look ok but I don't have a meter here with me to make certain but I'll bring one home from work tomorrow. That way I can check to see if the fan is getting any juice. I'm Kinda worried it wont because of the state of the wiring. The fan isn't ceased, so I'm hopeful that I won't have to replace it. I can meter that out too hopefully tomorrow. I just hope I don't have to resort to the switch and wire combo mentioned in the thread I linked to! I'm also on the scrounge just in case. I'll have more details tomorrow I hope. I just hope I don't get stuck in traffic on the way to work tomorrow Can't believe my luck with this car. Especially since I know I can repair it myself but I hgave such a short attention span that I usually end up taking it down to my local garage to get it sorted out. Which usually leaves me out of pocket. Link to comment Share on other sites More sharing options...
Guest robman1 Posted July 5, 2007 Share Posted July 5, 2007 dude i paid 1950 for my car and i get a diff problem every week i just replaced my radiator too, so talkin of luck u got it easy at least it was cheapish lol Link to comment Share on other sites More sharing options...
Guest robman1 Posted July 5, 2007 Share Posted July 5, 2007 have u checked all the wires on the thermostat, and that the thermostat is working properly? Link to comment Share on other sites More sharing options...
Guest PIP Posted July 5, 2007 Share Posted July 5, 2007 my mk 6 runs hot ish was told by ford its normal Link to comment Share on other sites More sharing options...
chaz Posted July 5, 2007 Share Posted July 5, 2007 Some cars can run hottish but should never go anywhere near the red, if your fan is not kicking in then maybe you have a faulty switch / sensor, this happened on my other car not the cab and all it was a faulty fan switch / sensor Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 5, 2007 Share Posted July 5, 2007 Well guys I got my trusty meter from work and had a poke around under the bonnet and here's what I found today: I confirmed that what I was looking at the other day was indeed the correct thing, the temperature sensor/switch. I know that because I used the meter to check the continuity to the fan from the thermal switch and from the other side of the switch to the chassis. This proves that the fan is controlled by the thermal switch making and breaking the neutral to the fan. The cable from the switch to the chassis is brown and the cable from the switch to the fan is brown/black by the way. So I expected to see voltage on the red/black live cable when I turned on the ignition. I didn't though, much to my disappointment. So I turned off the ignition and looked for continuity from the red/black to the fuse box. The fuse in question I am assuming is one of two marked with a fan symbol on the fuse box lid. Both are marked with the same symbol but one is a 25A and the other is a 10A. I assumed the 25A is the one I should be looking at and I didn't have continuity. I tried to measure voltage at the fuse box and there didn't appear to be anything there on either side of the fuse. This may just have been becaise I couldn't get good contact due to my probe being too large to fit into the fuse holder. Anyway, I decided to see if the fan worked so I bridged out the temperature switch and took a direct feed off the live side of the battery and dabbed it onto the fan. It sprung into life and ran away merrily. So the fan is working fine. I'm yet to verify the thermal switch is operating but it's pointless without a voltage on the live to drive the fan anyway. So that's it in a nut shell. But I have a feeling my problem my be more complicated than what it appears at face value. I have a leak that's letting water into the driver's foot well. And the water's getting in through, dun dun da... the fuse box! Not only that but the interior hot/cold air blower isn't working either (on any setting). So I'm wondering if these two faults are related. It seems strange that I don't have continuity back the fuse box from the rad fan, it's almost as if it goes off somewhere else first? Perhaps to the interior fan for the air blower? The only way I'll find out is either by more poking around with a meter or getting hold of a wiring diagram or haynes manual. I'm hoping the fault is something simple like a blown fuse due to water or damp casuing a short at some point in the past or a cable simply come off somewhere. Either is plausible given the situation and my lack of knowladge of how the circuit(s) are wired. The trouble with my leak is that the fuse box is actually cracked around the bottom tube-section which all the cables enter the interior through behind/under the dash. It's basically unrepairable so I could do with a new fuse box if anyone knows where I can get one. Preferably one fully loaded with fuses and relays etc. I'll have another poke around over the weekend and see what I can dig up. It sure helps being a sparky but it's so frustrating without any drawings so when i get paid it looks like I'm gonna have to splash out on some litterature! In the mean time if anyone has any knowladge on the electrical side of Mk3's or a fuse box they wanna sell... that fuse box looks like a right nightmare to change. It's gonna be a long summer. Especially if the rain don't let up. Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 5, 2007 Share Posted July 5, 2007 Oh and another thing. Does anyone know if the temp sensor/switch is a dual function temp sensor that also does the job of the thermostat and controls the flow of water around the engine/radiator? Reason being is that the car has been stood since 2004 and as you can imagine I think a few things have siezed here and there. When I got the car I decided I was going to do an oil change and flush out the radiator and replace the coolant straight away. I was going to do this anyway but then I noticed the car is taking a long time to warm up. I think the stat might be stuck open. As well as not knowing if it's one and the same component that I have been looking at the past couple of days I decided it's probably best if I replace the stat or even better both of these components when I flush the system out. Trouble is I don't know what's what around the engine bay because I don't have a Haynes manual yet. I think it's for the best if I replace everything I can in the cooling system as long as doesn't cost me an arm and a leg to do so. Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 6, 2007 Share Posted July 6, 2007 ok I took some pictures of what I've been looking at This is the temp sensor/switch Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 6, 2007 Share Posted July 6, 2007 And this is where it is on the engine: Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 6, 2007 Share Posted July 6, 2007 I got one more lol Oh and sorry for the poor light, it was about 2200 when I took them after I got home from work after all! Link to comment Share on other sites More sharing options...
Guest AKATheWolfman Posted July 6, 2007 Share Posted July 6, 2007 I ordered a Haynes manual last night before I went to bed and it should be here some time early next week. In the mean time I've constructed a switch and relay to control the fan from inside the car. It also has an LED to indicate when the fan is running that I've adapted to run off 12V using a 500 Ohm resistor I'm having trouble getting the cables in from the engine bay though so it can wait till tomorrow lol I did find out something more interesting tonight too and that is that one of the cables that feeds the air blowers in the dash is red/black too as well as a yellow/black and a green/black. I assume that these are the outgoing cables from a common feed controlled by the fan speed selector that is most likely red based on the format the neutral is wired on the sensor (brown from the chassis and then the cable that's switched by the thermal switch is brown/black). The switch just selects different windings on the motor by the look of things. But try as I might I can't find this elusive cable Link to comment Share on other sites More sharing options...
Vincygav Posted July 18, 2007 Share Posted July 18, 2007 The problem why the fan isnt coming on which you have solved is that the fan temperature switch has gone, they do go from time to time and seem to go when the engine is stood up for long periods like a few years, not sure if they get clogged in crap or something. The thermostat in the thermostat housing that the fan switch is onto is not controlled electronically. The thermostat works by opening and allowing water to pass through it when it reaches the preset temperature i.e. 86 degrees C, and then if the coolant temperature drops below this it would gradually close. I believe it is of bimetallica construction. The fan would cut in and off also at pre determined temperatures i.e. 82 degrees C. Other things I would advise if you have not done it, is get a new thermostat, should cost around £3-4, also full the cooling system, put new coolant in. PIP you can put a Ford Puma 1.7 thermostat and a Ford Escort Cosworth fan switch in your car if you want it to run cooler...assuming it is a 1800 zetec. The car would then run much cooler on the temperature guage and the fan would cut in more earlier. Link to comment Share on other sites More sharing options...
Guest Mk4 Rustbucket Posted August 23, 2007 Share Posted August 23, 2007 Well guys I got my trusty meter from work and had a poke around under the bonnet and here's what I found today: I confirmed that what I was looking at the other day was indeed the correct thing, the temperature sensor/switch. I know that because I used the meter to check the continuity to the fan from the thermal switch and from the other side of the switch to the chassis. This proves that the fan is controlled by the thermal switch making and breaking the neutral to the fan. The cable from the switch to the chassis is brown and the cable from the switch to the fan is brown/black by the way. So I expected to see voltage on the red/black live cable when I turned on the ignition. I didn't though, much to my disappointment. So I turned off the ignition and looked for continuity from the red/black to the fuse box. The fuse in question I am assuming is one of two marked with a fan symbol on the fuse box lid. Both are marked with the same symbol but one is a 25A and the other is a 10A. I assumed the 25A is the one I should be looking at and I didn't have continuity. I tried to measure voltage at the fuse box and there didn't appear to be anything there on either side of the fuse. This may just have been becaise I couldn't get good contact due to my probe being too large to fit into the fuse holder. Anyway, I decided to see if the fan worked so I bridged out the temperature switch and took a direct feed off the live side of the battery and dabbed it onto the fan. It sprung into life and ran away merrily. So the fan is working fine. I'm yet to verify the thermal switch is operating but it's pointless without a voltage on the live to drive the fan anyway. So that's it in a nut shell. But I have a feeling my problem my be more complicated than what it appears at face value. I have a leak that's letting water into the driver's foot well. And the water's getting in through, dun dun da... the fuse box! Not only that but the interior hot/cold air blower isn't working either (on any setting). So I'm wondering if these two faults are related. It seems strange that I don't have continuity back the fuse box from the rad fan, it's almost as if it goes off somewhere else first? Perhaps to the interior fan for the air blower? The only way I'll find out is either by more poking around with a meter or getting hold of a wiring diagram or haynes manual. I'm hoping the fault is something simple like a blown fuse due to water or damp casuing a short at some point in the past or a cable simply come off somewhere. Either is plausible given the situation and my lack of knowladge of how the circuit(s) are wired. The trouble with my leak is that the fuse box is actually cracked around the bottom tube-section which all the cables enter the interior through behind/under the dash. It's basically unrepairable so I could do with a new fuse box if anyone knows where I can get one. Preferably one fully loaded with fuses and relays etc. I'll have another poke around over the weekend and see what I can dig up. It sure helps being a sparky but it's so frustrating without any drawings so when i get paid it looks like I'm gonna have to splash out on some litterature! In the mean time if anyone has any knowladge on the electrical side of Mk3's or a fuse box they wanna sell... that fuse box looks like a right nightmare to change. It's gonna be a long summer. Especially if the rain don't let up. On my Mk3 1985 1.6i the 25A fuse with the fan symbol is for the heater blower so you could be checking the wrong 1 of the 2 (i'm assuming you've fixed it by now though LOL) Link to comment Share on other sites More sharing options...
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