These new production hoses have a larger thumb screw on the vent.

It's just been pointed out to me that there is a really easy way to effectively bleed a Murena cooling system - wrap some tape around a piece of rubber hose so that it makeas a good seal with the header tank filler hole. Make sure the water is topped up, then blow hard. Bubbles will come back into the header tank through the small pipe from the radiator. That's it...

Matra part 32727400 remanufactured in silicone rubber