Fan on too much

xJib

Full Member
The other day I noticed sitting in traffic the fan was not cutting. I tested it at home by running the car stationary for ages but the temperature gauge never went over normal, but the fan never came in. So I've change the fan switch that screws into the radiator and now it cuts in when I'd expect it to. I've got the other problem now of the fan on too much.

I don't think that it's overheating (though not positive) and have changed the thermostat and water pump as I thought that they were the problem. Also I have removed the radiator and made sure that water cold easily flow through it.

The big problem is that the fan stays on when you park the car and the other day managed to flatten the battery!

Could the new fan switch be faulty? If so how do I test it?

Or is there something else I'm completely missing?
 

xJib

Full Member
could be fan switch but we had a problem like this, turned out to be the bottle blocked, nice easy fix to do :)

Thanks GTV, I'll have a look later.

might just be a broken temp sensor, probably wrong but thats what id check first

The temp sensor I think is working, as if I unplug it the the gauge stops working. It's just odd that it never goes over half way. Maybe the gauge in the car is faulty?
 

xJib

Full Member
So after much scratching of heads it's now been fixed.

Turned out that the the fan switch that I bought from Euro Car Parts was coming on at too low a temperature and so keeping the engine cold and not letting the stat open.

From looking at it, it has the correct part number stamped on it 1H0 959 481B, but that was it. After searching round the internet I cam across a PDF (link below) of a Chinese OEM manufacture that makes them (though have no idea if they make the one I have) and they list the same part number but with two different temps, one that works at 85-93°C and one that works at 95-102°C, so I'm guessing I have the low one of the two as the stat doesn't even open till 87°C, after the fan had come on.

So I got a genuine part from the local Seat garage, Holders, and that had the same part number stamped on it, but also the operating temps. And this has cured the problem of the fan being on all the time.

So after fitting the wrong part I've replaced the stat and water pump, flushed through the whole system, replaced the header tank, drilled a small hole in the new stat to make sure there wasn't an airlock (vwvortex forum tip), swapped the fan switch and finally replaced the stat for one without a hole. Now all I need to do, at some point refill the whole system with antifreeze.

Not all was lost, I now have a good working cooling system with no blockages all ready for the scorching summer we're going to get, and I can now also remove a water pump in less than 10mins :D


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