I have a Fiat Punto which has a problem with an airlock in the cooling system. I have drained and refilled, and bled the system, but after a few days the airlock keeps returning. Any thoughts on why this keeps recurring?
Car runs fine. After a couple of days, starts to overheat, so I bleed cooling system and everything fine for a few days, then engine starts to overheat again.
Have it checked for a leaking head gasket. If combustion gases sneak into the cooling system, the thermostat may close leading to the overheating. Thermostats only open in response to hot liquid. The air can also cause circulation to stop even if the thermostat remains open. The clue to a leaking head gasket is you have to repeatedly bleed air from the system. You might also see air bubbles in the reservoir when the engine is running.