Ford Fiesta Heater problems

That'll be the valve type gadget - a common fault on them. Don't know how expensive or easy it is to fix as I never bothered on my Mk5 W reg Fiesta van that I had.

I've got loads of ideas. Many other people do too, so yes.

About your question then - you say it's erratic - it wouldn't happen to rise when you're sat in traffic, would it? Temperature gauges do that.

Peter

Maybe also an air lock, or a stuck thermostat ?

Graham

Sounds like your thermostat is stuck open, so the engine is never warming up properly. Check just inside the oil filler cap for a mayonnaise like substance - thats what happened to my K plate fiesta.

The other symptom was that the hot air from the heater was not as hot as it used to be, if that makes sense.

Rob