overheated but dont think its the fan

[dainott2105]

Right might take a while to explain so sorry before i begin. I was driving home on saturday (very hot day) about midday (first time id driven the car that day). id been about a mile and decided to turn on the air con (first time ever, other than a few seconds to see if it worked) as i came onto the motorway. Must have driven about 7 miles and the temp gauge started to go up and got to 3/4s so i quickly pulled onto the hard shoulder and knocked the engine off. opened the bonnet so it could cool a bit. left it for 5 and then drove off with the aircon off and the heaters on full heat. temp was fine until the missus comlained that she was boiling and so i knocked the temp down to 23 (no aircon still) and after about another 2 miles, temp gauge went up again, so pulled over again. left it again and then was able to drive to my house (3 miles or so) with the heaters on full heat again. i looked on here and found a link about the fans failing so thought that it was the issue, but i checked the fans last night (p.s. i havent driven it since) and both seemed to run fine, and i ran the engine for approx 20 mins with the air con on hot, cold, on/off and the temp needle didnt move from 90. The fans kept going the whole time. So now im really puzzled as to what caused this. I have ordered the resistors to bypass the internal ones in the fan that burn out all the time (rapid electronics are the cheapest for them, (£3.45 each, order code 62-8176)) and im getting vagcom tomorrow to check if there are any sensors gone, but wondering if anyone had possible causes of this or a known fix. Cheers all

 

[Tam]

Water pump propeller ?

 

[goble]

fuse box or as above^^^^^^

 

[dainott2105]

How much is the water pump propellerthen? and is it diy or garage? also would the water pump be noisy on start up then, cos i have a noise for about a minute when i start it from cold (sounds like a diesel) which i thought was the secondary air pump, but never had any probs once it stops

 

[Pabs]

did the alarm actually go off? Or did you pull over before that happened?
Do you have an FMIC?

 

[dainott2105]

as i stopped the alarm beeped, but it went off just before turned the engine off. No mate no FMIC yet. any ideas?

 

[Pabs]

definately waterpump then.

While your replacing that, get the cambelt and tensioner done at the same time - seeing as it all has to be removed to replace the waterpump anyway, may as well change it

Suggest the brass/metal impellar'd waterpump - much stronger than the std plastic one.

If your paying a garage to sort it, be prepared for quite a large bill - it'll take a good few hours labour for the job, + parts etc.

 

[neil]

mine was done 2 weeks ago with all seat parts (apart from metal impeller'd water pump) and was £261 all in

 

[bigfella_V5]

If the fans are running all the time. Especially if the air con is on and the engine is cold (one should run slowly) there are no fan resistor faults.

See here:

http://uk-mkivs.net/forums/3/449470/ShowThread.aspx

 

[dainott2105]

cheers was worried that i wouldnt find the prob, im gonna do the fan mod aswell as the resistors arrived this morning. Where do you get the metal blade pump from then folks

 

[bigfella_V5]

I don't think I will do the fan mod. Will just get new fans I think.

 

[bigfella_V5]

I've also heard that the fan control box can be at fault and I'm pretty certain it is on mine. I will replace that and the fans. And if the resistors do burn out again I will do the fan mod.

 

[bigfella_V5]

Ouch, just called the dealer and they are around £115 each! The fan controller is also around £90!

 

[dainott2105]

fan mod it is then i take it !! has urs got the same problem as mine or are the fans not working on yours. Anyone know where i can get the metal blade pump from? cheers

 

[bigfella_V5]

Yeah I will have to do the fan mod. I need to get hold of that heatsink plate. The problem with mine is that neither of the fans work.

I have tested the fans and indeed the slow speed is faulty. But also mimicked the car getting too hot by bridging connections on the radiator temp sensor plug and no power seems to be getting down to the plugs for the radiators.

All fuses have been tested and there is no damage to the fuse boxe(s).

So I'm quite certain it needs new fans, or the fan mod plus the fan control unit.

 

[dainott2105]

so can you get the fans on constant at the mo or are they not working full stop mate. Also do you know if its the same design plate for the leon cos the plate diagrams for the golf aint it? My old man is gonna make mine so il see if i can knock you one up at the same time. Just dont want to make them and find they dont fit

 

[bigfella_V5]

I'm not sure if the plate is of the same design, I don't think it is because I believe the Bora differs from the golf. I believe there may be space in the same area below the headlight on the battery side. The horns are there so they will probably need to be removed first.

The fans don't appear to be working full stop, they do work if I run a temporary live down to them as a test, but only on full speed.

So that shows that the internal resistors are faulty but it doesn't answer why there is no power getting to them this makes me think its also the fan control box / ecu at fault.

 

[dainott2105]

mmm, yea see what u mean. Have you checked to see if you have power before it reaches the control box. Yours seems like it coould be a right nightmare to sort , but i would do the mod which means u wont have to shell out on new fans and have a look for a leon or toledo being broken (get the part number and phone seat and ask if the control unit is the same on all models with climate) and should get the control unit for cheap. If it dont sort it cant see you having a prob selling it if there are reported issues with the box. Strange thing about mine is that it overheated the other day but i drove it last night and left it running with the aircon on and there were no probs, so i dont know if its a dodgy connection somewhere. got an auto electrician (mate) coming to do some diagnostic testing after, see if there are any sensors gone or error codes coming up. dont want to have to change the water pump unless it def that, but pabs seems sure it is, so see what he says tonight and go from there i suppose

 

[bigfella_V5]

I agree, but its going to be a mission to do it, but I think I will have to.

I have a mate that works for VW and just want to confirm my thoughts first.

Let me know how you get on with making a plate/heatsink up as I'd be really interested. Then all I'd need is the resistors, wire and some of that tube/loom covering to make it neat.

I have a good idea how they wire up in my head as I've had a good look at how its wired up.

 

[dainott2105]

yea no probs mate, il see what i can do for you. Order the resistors from rapid electronics £3.45 each, order code 62-8176 cos they are the cheapest ive seen and had them next day(i ordered some torx tools aswell for the free delivery). If i get the plate sorted for you il post you some new wire (just bought a 100m reel) aswell. il have to get some of that tube aswell (good idea). Il let you know how he gets on with the checks tonight aswell and ask him about urs and let u know