Hi All

My first post here but have been checking it out for some time.

I'm currently in Czech and I have a '92 Favorit.

I noticed yesterday as I was driving down the motorway that my temp was a little over the 3/4 mark by the time I had got home and the fan wasn't kicking in.

I tested the fan following some instructions on here and it works perfectly. My next port of call is the switch that's on the radiator. I have ordered a new one that should switch at a lower temp (the old one looks pretty corroded to be fair. I am not sure if there is an easy way to to test it but for the price of a new one I thought it's better just to replace it.

So when this part arrives I will need to fit it....

I presume I have to drain the radiator. I read that it may be better to drain by removing the hose rather than using the plug as that tends to snap due to corrosion.

Are there any other things I should be aware of before changing this switch? any tips would be appreciated.

Thanks

This might sound odd, but have you checked the anti-freeze concentration? I'd recommend using 50/50, because anti-freeze acts as a "water wetter", and raises the boiling point and heat transfer co-efficient of the coolant.

Also, if you are going to drain and refill the system, flush it when you're there anyway.

I think you've got a bit of a blockage if the car is going onto heat at cruising speed.

This might sound odd, but have you checked the anti-freeze concentration? I'd recommend using 50/50, because anti-freeze acts as a "water wetter", and raises the boiling point and heat transfer co-efficient of the coolant.

Also, if you are going to drain and refill the system, flush it when you're there anyway.

I think you've got a bit of a blockage if the car is going onto heat at cruising speed.

Anti freeze level should be ok I am pretty careful with that as the winter temps get pretty cold out here.

The temp doesn't get into the red at all, I must admit. I would just expect that the fan would kick in around the 3/4 mark, maybe it's higher?

My plan is to flush it out.

How would I check for a blockage?

I'm not certain, but I'd expect the fan to kick in just before the needle hits the red sector.

The flushing should remove the sort of blockage I'm thinking of, which is every element in the radiator core being slightly blocked by silt, rather than,say, one being blocked solid.

I would just expect that the fan would kick in around the 3/4 mark, maybe it's higher?

I don't know how the gauge is marked but on our Felicia the fan starts when the needle points to about 110.

I don't know how the gauge is marked but on our Felicia the fan starts when the needle points to about 110.

lol think mines to old for actual temps! it goes from white to red no markings lol

@Ken, I have a suspicion you are right the more I read I see they get quite hot before it kicks in.

I will fit the new one anyway now it's ordered and it will give me a good excuse to flush it out. I have a feeling it probably hasn't been touched for many years.

Dom, I've never owned or driven anything with an ungraduated temp guage that would move significantly from "normal" (for it) on flatish motorway; going on heat usually happens in traffic or up steep hills (the sort of thing that puts you down 2 gears from what you need for that speed on the flat) which makes me think your cooling system's not right, but a flush and new 50/50 antifreeze and water should sort it. With an electric fan, it doesn't usually cut in until 110C (graduated gauge) or the edge of the red sector (coloured but not graduated guage).

Dom, I've never owned or driven anything with an ungraduated temp guage that would move significantly from "normal" (for it) on flatish motorway; going on heat usually happens in traffic or up steep hills (the sort of thing that puts you down 2 gears from what you need for that speed on the flat) which makes me think your cooling system's not right, but a flush and new 50/50 antifreeze and water should sort it. With an electric fan, it doesn't usually cut in until 110C (graduated gauge) or the edge of the red sector (coloured but not graduated guage).

Yeah it generally runs just above the middle of the white area. I will give it another little run out on the way back from work and see.

Cheers for the tip about when the fan cuts in. It definitely is near enough the red to kick in by the sounds of it.

I will give the flush out a go and let you know what goes on.

Cheers

Yeah it generally runs just above the middle of the white area. I will give it another little run out on the way back from work and see.

Cheers for the tip about when the fan cuts in. It definitely is near enough the red to kick in by the sounds of it.

I will give the flush out a go and let you know what goes on.

Cheers

Well didn't flush it yet. Found out the thermostat was shot.

New thermostat installed (and new clutch but that's another story) the favorit is running like a dream and all working again without heating up lol