Ford Fiesta Saloon - Fiesta coolant problem

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Thu 12 Aug 2010 12:00
Ford Fiesta Saloon - Fiesta coolant problem - Dobro

Hi,

Can any one help?

2006 1.4 Fiesta Diesel

At the end of a journey a small amount of coolant is deposited on the floor - enough to lower the level from Max to about half way towards Min. I think it comes from the header tank vent, (if it was a leak I think the whole system would be empty before I got home). It's as if the radiator fan doesn't come on at the end of a journey causing the residual heat in the engine to cause the coolant to boil). I have run the engine up to normal temperature from cold while stationary and there is no leak. I disconnected the temperature sensor lead with the engine running and the fan comes on in safe mode. This seems to suggest that the fan, relay and fuse are okay. I changed the sensor but that didn't help. The thermostat appears to work in that the top hose is cold until the engine warms up and then it becomes hot. The temperature gauge never goes above normal.

At the same time the aircon is not working. With the engine on, the heater fan on and the aircon button lit up, I believe the radiator fan should operate but it doesn't.

Everything seems to point to the radiator fan not switching on when it should - but why.

Any suggestions gratefully received.

Dobro

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Thu 12 Aug 2010 15:28
Ford Fiesta Saloon - Fiesta coolant problem - madf

If it's wiring is anything like my Yaris, there are two relays which control the fan: one with aircon on and one with aircon off.

It could be the first (aircon on) has failed... Check handbook or wiring diagram and test ..

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Thu 12 Aug 2010 16:13
Ford Fiesta Saloon - Fiesta coolant problem - bathtub tom

Could be an air lock causing the excess to be expelled, but that won't explain the air-con not working. I'd suggest you fill to the max mark when hot. Mine drops a fair way when cold, but returns to max when hot.

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Thu 12 Aug 2010 18:56
Ford Fiesta Saloon - Fiesta coolant problem - Dobro

Thanks bathtub but if there was an airlock I think the engine would overheat and it would show on the temperature gauge.

I may be wrong about the coolant coming from the headertank overflow - coolant is sprayed everywhere so it's difficult to see where it's coming from.

If I could get the fan to switch on with the aircon I could eliminate it from the coolant loss problem.

Dobro

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Thu 12 Aug 2010 18:44
Ford Fiesta Saloon - Fiesta coolant problem - Dobro

If it's wiring is anything like my Yaris, there are two relays which control the fan: one with aircon on and one with aircon off.

It could be the first (aircon on) has failed... Check handbook or wiring diagram and test ..

Thanks madf but it looks like just one relay.

Dobro

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Thu 12 Aug 2010 18:50
Ford Fiesta Saloon - Fiesta coolant problem - Collos25

My switch lights up when the AC is not in use

Edited by Andy Bairsto on 12/08/2010 at 18:55

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Fri 13 Aug 2010 08:53
Ford Fiesta Saloon - Fiesta coolant problem - Dobro
Does anyone know if the aircon has a failsafe system that stops it operating if all the gas has escaped preventing it from damage? If it has then this could be why the fan doesn't come on and has nothing to do with the leak.

I'm now thinking that the coolant leak occurs all the time but is very small and that, when I stop, the coolant that has sprayed all over the engine drains onto the floor and gives the impression that it only occurs at the end of a journey.

Anyone any ideas?

Dobro
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