307 Where is the Bleed Valve? Engine Coolant

[findmak]

I think I have an airlock in my 307 1.4 2004 model Petrol, as the Engine coolent was totallt empty once, I have topped it since but occasionally when driving the temperature goes through the roof (into the red area) then comes back down after a few seconds.

Where is the Engine coolant bleed valve located, I see a thin pipe go from the coolant bottle to the radiheater, but can't seem to find the bleed valve.


Thanks