Rad fan not working

[patters1978]

Hi guys

My moms TDI fan has stopped working i have bridge the connections and the fan works on both low and high but just doesn't come on by itself

After some reading i'm drawn towards the fan switch being at fault? bit of a guess

but how do i test it and replace it?

cheers

[itavaltalainen]

Fan switch is highely likely, or then could be a broken wire. Replacing the switch is a case of you getting the engine code from your cambelt cover or service book and looking for the correct part, buying it and just replacing it - it's a fairly quick in / out job. Some loss of coolant (so have some ready, dont just top up with water) but if done quickly not dramatic. Also buy a new o-ring, after all these years in there it is just waiting for you to take it out and put it back in to start leaking afterwards.

If you're having trouble finding the correct one let me know engine code and built year - that would be letter in your VIN where the star is here:
wvw zzz 1h z * w 000 000

[patters1978]

cheers for the reply bud

i have looked on eurocarparts but there seems to be a few so ill get you the vin number when i see my mom later

Can the car still be driven? or can something be done as a temp fix? she works weekends so needs the car its a 20 mile journey motorway but to be honest i dowt she goes over 60 mph lol

[patters1978]

right drama

managed to get the part but .... tightening it up but it didnt seem to get tight? now the thing wont unscrew? 
help

[itavaltalainen]

crossthreaded?

[Bandit127]

Thread stripped. 

If it is like the V6 Omega one they go in to a plastic thread - but have a whacking great big brass nut on (22 mm?) that looks like you can hang off it with a spanner to do it up. WRONG!

OP - physically (and gently) pull it outwards as you turn it to undo it. Your aim is to engage it in what thread is left in there and no more. Once you have caught the thread it should undo so you can get it out.

If I am right (and you are lucky) it is a plastic thread and there will be enough left in there for a bodge...

Wrap the thread on the fan switch in PTFE (plumber's) tape - at least 5 times round. Then start it in what is left of the thread carefully. Do it up by hand as tight as you can. Then grab a spanner - but hold it end-on instead of by the handle. Use it to very gently tighten the switch until you feel the slightest extra resistance as it reaches the seat. Hopefully the PTFE tape will have filled out what is left of the stripped thread and made it water tight.

Top the water up, replace the cap and run it up to temp. Look for leaks.

If it doesn't work you will need to replace what bit the thread stripped in. On the Omega that would have been the rad...

Good luck and let us know how you get on.

[Jasikasisback]

i think i have the same problem...as the fan just comes on very very rarely now...

[patters1978]

cheers bandit127 i shall give it a try today and let you guys know 

i thought the things was going into the rad and would tighten! didn't realize it was just plastic

how easy is it to replace rad cuz i have seen one going cheap.. also do the rads differ over the models? ie can a petrol one fit a diesel

[itavaltalainen]

The mk3 has quite a number of different rads... i.e. they will have different width and thickness.
Which one you need depends on a few things, which engine you have (engine code), tow bar, automatic, a/c....

Post which engine code you have and any extras on the car and I'll look it up for you. Or call VW, give them your VIN and they check from VW database in Germany what's in your car.

[patters1978]

ok cheers guys

does anyone know a way to test the old switch? its my understanding that at normal temp the circuit is closed but once it gets to a certain temp it opens..
does this action happen without power to the switch? could i stand it in boiled water to test it