when idling (& probably when revving but it's too loud) I can hear a low dull thud every approx 5 seconds when sat at the drivers seat . With the bonnet open, if I hold the cooling/heating pipes near the wiper motor arms (heater matrix maybe???????) I can feel the thud through the pipes, it cannot be felt through any of the other cooling system pipes, any ideas?????
Tracy
It's the heater control solenoid valve, located just behind the bulkhead where you've been poking around.
It opens and closes in order to control the amount of hot coolant into the heater matrix. Adjusting the temp control knob adjust the relative timings of the on/off (open/'closed'[1]) positions.
At least whilst you can hear/feel it you know it's probably not knackered... a common failure point on Fiestas.
Mathew
[1] It doesn't actually close, but rather circulates the coolant straight back down the return pipe instead of via the matrix.Cheers. makes sense too me, will try adjusting the temp control knob just to make sure Thanks again
Tracy
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