tick-over/ temperature

[ack351]

Hi, i'm not the most experienced when it comes to cars although in general i'm quite technically minded (i'm an electrician). Anyway i've just bought a mark4 polo for my girlfriend and there is a couple of issues i want to fix before i give it to her.
1. The tick-over in idle is low, can i turn this up and if so how?
2. The fan doesnt kick in, so unless you drive with the heaters on full belt it will over heat. The bloke i bought it from said he had it to a garage who linked the fan out to confirm it was ok and it was, apparently he changed a sensor and said it would be ok, but it is not, dont think he'd checked it. Anyway if anyone could help on these 2 problems i would be very gratefull
Thanks.

[really wants an RS6]

Check the sensor by pulling the multiplug off it, it will have 2 or 3 wires(1 supply in and 1 or 2 out to the fan) depending on whether it is a 1 or 2 speed fan, get a paperclip or something similar and short these together,the fan should come on. If it does then it's the sensor, if it doesn't check the supply to the sensor with a multimeter.

[ack351]

shorted out the fan and its ok, what should i expect to see on the supply?

[Boardboy]

If you've shorted the fan and it's working, it's more than likely to be the sender on the rad. I've just replaced one on my girlfriends Golf MKIII.
It was £9 from a local VW specialist. Mine needed a 29mm socket which isn't a common size. It should come with a copper crush washer on it.
Hope this helps
Boardboy

[ack351]

I was told that this sensor had been changed already? Is it possible the bloke i bought it from was full of sh** or is it possible something else is faulty? maybe blocked radiator so flow is not gettting near the sensor? Any ideas or should i stick with the sensor theory for now?
Thanks

[Eshrules]

I was told that this sensor had been changed already? Is it possible the bloke i bought it from was full of sh** or is it possible something else is faulty? maybe blocked radiator so flow is not gettting near the sensor? Any ideas or should i stick with the sensor theory for now?
Thanks

TBH id assume the guy was full of it.... for the sake of a tenner, id get the sensor and change it anyway, just to confirm it.... if the problem is resolved, bingo, if not, you know for definite it isnt the sensor and you can set about checking the rad and pipes for blockages.:beerchug:

[carl]

You should check the thermostat before you go any further if it is not working the water will not pass into the radiator to reach the sensor to activate the fan. Also check the pressure cap if it is not making a good seal the system will not pressurize and this can cause overheating and is often overlooked.

[ack351]

I've checked the thermal switch and its working as it should. I even linked the switch out, so the fan was on permanent, then drove it. It still over heated though. I've checked the cap and it is sealed fairly tight. Any other suggestions. I do not like running the car like this (apart from it being red hot with fans on full belt) i am worried i might do more damage.
I'm open to any advice.

Thanks

[Huweth]

Water pump?