My Fiestas heating keeps running hot and then cold. A pisser, as you can imagine, at this time of year as it's now frosty most mornings.

Car reaches operating temperature, interior heats up. With heater on same setting the car then cools right down, then heats up, then cools down etc totally randomly. HELP!

It is a 1.25 zetec 1997 car.

Any suggestions as to what might be causing this? A sticky thermostat perhaps?

Your help shall be warmly recieved


Cheers,
Pete.