1.25 zetec - Mk4 fiesta zetec heater

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Fri 9 Nov 2012 20:17
1.25 zetec - Mk4 fiesta zetec heater - gasspringmaker

Can anyone give me some advise?

I have a mk4 zetec fiesta and have recently been having problems with the heater.

When ticking over and driving at 30-40mph the heater is fine.

But when you get over 40 mph or 2500 revs it goes cold.??

Ihave replaced the thermostat today as the bottom hose doesn't get warm and was told it could be sticking.

But when driving it home the problem is still there.

Any advise will be appreciated.

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Sat 10 Nov 2012 12:56
1.25 zetec - Mk4 fiesta zetec heater - Peter.N.

If the bottom hose doesn't get warm that is a good indication that the thermostat is working, it should stay closed until the water reaches normal working temperature and then open so it will only get hot when under load or after idling for some time

The fact that the heater goes cold at at high revs would seem to indicate some air in the cooling system, did you fully bleed the system after replacing the thermostat, including the heater pipes? Otherwise you may have a faulty heater control valve.

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Sat 10 Nov 2012 13:20
1.25 zetec - Mk4 fiesta zetec heater - gasspringmaker

I have fitted a new heater control valve about a month ago.

Had a heat test done on it this morning and it is circulating fine but not getting hot enough , 63 degrees .

So mechanic suggested to test thermostat to see what temp it is opening at.

But meens spending more money on it.

I might get another thermostat from a different supplier and see what happens with that.

Just cant see why over 2500 revs it goes cold and the bottom hose is cold too.!!

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