How can I fix my Peugeot 206 - STOP warning light keeps flashing?

First of all have a look at the state of the oil on the dipstick, if it is anything less than soot black i.e yellow, creamy, white or foamy the head gasket has gone, probably due to overheating knowing peugeot's. If the oil is black, top up the water level to full, park the car on some clean, dry ground, run the engine until full working temperature is reached, look around the engine bay at all the rubber pipes and under the engine for coolant dripping, also it may be worth feeling the carpet in the driver and passenger footwell as the internal heater matrix's can leak, none of this will be cheap to fix. You could always try putting in a bottle of radfix which you can buy in halfords for a few quid, it's not guaranteed to work but it did on my 205 for at least six months when I had a dodgy radiator.
Good Luck

Lee
August 2007