Hi I hope somebody has come across this before.
My friend has an R reg Seicento 900cc and it keeps over heating because the fan wont kick in.
Its had the radiator switch replaced and the thermostat housing switch replaced also butthe fan is still lifeless. :bang: If you short the fan then it works.
Could it be the thermostat itself? Or if anybody has any ideas then your help would be appreciated :worship: as my friend is about to blow a gasket herself!

I can see two likely possible causes.

The cooling system has very little water in it.
The wiring to the radiator switch is faulty (could just be corroded connectors).

I'm unsure of what you mean by the thermostat housing switch. When you talk of shorting out the fan, exactly what do you mean? What did you do?

It's not the thermostat. Or, at least, even if the thermostat is fubar, it shouldn't stop the fan coming on in traffic.

I have the same car and problem. Have replaced Thermostat with new. Hot water does not seem to circulate through the radiator. Radiator gets hot on top, but hardly at all at the bottom. I'm beginning to suspect a cooling pump with broken impellor blades.

The 899 is an external pump so its easy enough to change.

Also check that the radiator is actually passing water (prostate issues?). Could be blocked rad.

Cheers

SPD

Hi did you manage to solve this as I have changed everything on mine and still can not get the fan to work unless I bridge the terminals.

Not yet, life is very busy! My radiator is not blocked, (flushed that), the heater is not (flushed that) The thermostat has been replaced, with no difference to the symptoms. The radiator fan wil come on if I short out the sensor lead. The only remaining possibilities are the switch on the radiator is not working and the cylinder block water passages are actually blocked.... or the water pump does not work/is blocked. I'm just waiting to buy a cheap pump from somewhere...QH sell a new one for around £20 + P&P I imagine...I'll test the switch this weekend with a meter or battery, light and some hot water and a thermometer.
Another solution is to wire in a manual switch for the fan, so that you can turn it on when necessary. Mine manages to cope with daily to and from work and continuous reasonable speed driving, just overheats when stood in traffic

gmarshall5000 said:

, just overheats when stood in traffic

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Ah, this might be the answer. 899 pumps get weak with age. They can't shift enough water at idle. Does a fast idle solve the problem?

Manual switch will not solve the problem.

Cheers

SPD

I have replaced everything on mine and I know think the headgasket may be gone as the water boils if I release the pressure when hot and smells of exhaust fumes, it's fine in all other respects.

This has to be the only logical explanation, has anyone tried kseal as fix.

alfa156v6 said:

I have replaced everything on mine and I know think the headgasket may be gone as the water boils if I release the pressure when hot and smells of exhaust fumes, it's fine in all other respects.

This has to be the only logical explanation, has anyone tried kseal as fix.

Click to expand...

I did in my youth. IT cured the problem and got me back to uni for ages till i crashed it

Ming

What about Holts Wonderweld, for £12.99 it's got to be worth a try.

alfa156v6 said:

What about Holts Wonderweld, for £12.99 it's got to be worth a try.

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Not even at £0.01 is it worth a try.

Cheers

SPD

rallycinq said:

Not even at £0.01 is it worth a try.

Cheers

SPD

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Is this because it doesn't work in general or just this product, I have only to get my daugter through the summer and if this works it is a cheaper option that a headgasket repair for which I have been qouted £500+.

alfa156v6 said:

Is this because it doesn't work in general or just this product, I have only to get my daugter through the summer and if this works it is a cheaper option that a headgasket repair for which I have been qouted £500+.

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£500 are they going to wipe for arse with golden paper for that

on euro car parts you can get the following for £91.81;
'headgasket set
'head bolts
'waterpump
'thermostat
'oil
'oil filter
depending on how good you are with a spanner heres a guide that i made
https://www.fiatforum.com/cinquecen...977-cinquecento-899cc-head-gasket-change.html
Ash

Hi Ash I am aircraft fitter by trade so have the skills to do the job, how long wouold you expect it to take if doing one for the first time.

alfa156v6 said:

Hi Ash I am aircraft fitter by trade so have the skills to do the job, how long wouold you expect it to take if doing one for the first time.

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Less time than it takes to fill in the paperwork for anything you touch on a plane.

Cheers

SPD

alfa156v6 said:

Hi Ash I am aircraft fitter by trade so have the skills to do the job, how long wouold you expect it to take if doing one for the first time.

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5-6 hours tops, i would also recommend checking if the head is warped when it is off if its not bad id say dont bother or you couls just for piece of mind (£25-£30 for a skim)

you wont have to worry about timing on these old engines which is a advantage

Ash

Nah, hour off, hour and half back on. Split the manifold from the down pipe rather than try and undo the manifold from the head till the head is on the bench.

I think Ming had it down to half an hour to get the head off with experience.

If the OP has ever worked on a BL A series, it will all be very familiar.

Cheers

SPD

rallycinq said:

Nah, hour off, hour and half back on. Split the manifold from the down pipe rather than try and undo the manifold from the head till the head is on the bench.

I think Ming had it down to half an hour to get the head off with experience.

If the OP has ever worked on a BL A series, it will all be very familiar.

Cheers

SPD

Click to expand...

well was
5-6 hours for me with doing the guide (writing down and pictures)

+1 on splitting the downpipe from the manifold

Ash

Before I bite the bullet and do the head gasket do you guys think this will cure the mystery of the fan not coming on.

As I have replaced everything else I can't get my head around why the engine overheats but the fan does not come on.

Recap for me, please.

Your car overheats, i.e. the light comes on?

Does it only loose water when you release the cap?

Cheers

SPD