Why does heater in my Ford Fiesta go cold when engine is idling?
It is a 2000 zetec 1.25 model. The heater works fine when the engine has warmed up and the car is revving. However at idle, for instance in traffic or at lights, the air turns cold. I presume it is a dodgy thermostat or valve somewhere but dont know where
I would say its the coolant level first off. When the engine is cool enough open the Radiator cap and fill up to as full as you can,put the cap back on, then fill the reservoir to full mark. If the Radiator was low and you had plenty in the reservoir