Radiator fan not working.

[Judderi]

Right all i know is that it was working on friday but isnt now. I dont really know how the system works so could somebody please explain it to me and give me some pointers of things to check. Ive already checked that the plug is on the fan motor and also the plug on the thermostat at the bottom wing side of the radiator. Its a valver too if that makes a difference.

I know its not working cos i went to top up the water. I usually leave the filler cap of and wait for the fan to kick in then stop then put the cap back on but the fan didnt kick in and my water bubbled and boiled everywhere and i had to fill it all up again. Plus on the way to work this morning i had to stop at some lights and the temp flew up and worried me a little.

[rubjonny]

Its very simple
There is a permanent live feed direct to the rad fan sensor on the bottom of the passenger side of the rad, which then goes to the fan itself.  To test it unplug the temp sensor & bridge the pins, if the fan spins then you know the fan & wiring is ok, and the fault lies with the radiator temp sensor.  If not then run 2 wires to the fan direct from the battery, if the fan still doesn't spin then you need a new fan, if it does then you have a wiring fault somewhere.

It is possible for the header tank to boil over without the fan cutting in if you have an airlock, though if it still doesn't cut in when the gauge gets over 3/4 then it needs looking at.

[Judderi]

Right i bridged the contacts like you said and the fan whizzes up a treat. So does this mean my thermostat is shagged? Can they be repaired? i.e clean them up? Or should i just put my hand in my pocket and buy a new one. Ive also seen these littel buggers that claim to come on sooner and keep the engine cooler. Are they worth the upgrade?

Im a bit confused though. Which do i need the switch or the thermostat? And what does it mean by 3 pole? My fan is only a single speed

http://www.awesome-gti.co.uk/shop/customer/home.php?cat=254

[rubjonny]

You need the switch, and the one from awesome is no good as your fan is only single speed.  You could try cleaning it up if you want, but you'll loose alot of coolant while you sand all the crud off it

You could also upgrade to a dual speed fan if you want though, all you need is the radiator switch, loom & fan.  The loom ugoes to a 2 pin plug clipped to the RHS of the radiator fan shroud, near the battery.  Just unplug it here & plug in a 3 speed fan loom, found on most 8v MK2s

[Judderi]

Think i will just get a new switch from vag. Might give it a clean 1st though cos im tight.

[Dan34]

huge thread revival here but a quick question

ive got a mk2 golf gti 8v and when in slow moving traffic the coolant guage gets pretty much up to 3/4 and i dont think the fan is kicking in, should it kick in at 3/4? also am i doing damage to my car if i let the temp get this high?

Thanks in advance
Dan

[Dan34]

also forgot to add that my temp guage doesnt always work i no this is most likly due to temp sender but would this affect if my fan comes on or not?

Dan

[rubjonny]

dash sensor and fan switch are seperate things, the fan should kick in around 3/4 yes, but that depends how accurate the dash gauge is.  You can test the fan by bridging the red wire on the fan switch to the other pin(s).  Also feel that side of the radiator, if its a lot cooler than the hose end it may be blocked and so prevent good circulation of coolant.

[Dan34]

cheers rubjonny i was waiting for your help i had a new cambelt, waterpump and thermostat fitted today so im guessing its going to be an electrical problem il check out all the connections are go from there

thanks for your help

Dan

[Conker]

Keep an eye on your oil temp on the MFA - that'll give you an idea of whether your engines getting as hot as your water gauge is indicating. My MFA temp at the minute doesn;t go above 95, but in summer it gets to 110 in traffic, so I guess somewhere in that region is fine.