I am an old HVAC mechanic and for years I have muttered that the bleeding system for these vans cannot have been made by the same people that built the V2... IMHO it is a bozo system ... 

I am going to retap the radiator plug to 1/8 or 1/4 ips/npt ... the smallest that works... then I am going to install a low profile automatic air bleeder ... the type that has been used in hydronic heating systems for years.. this change to pipe threads from the fatherland fitting will enable anyone to cobble up a manifold of some sort to add or remove air or coolant at will... the auto bleed fittings are easy to remove and replace and have been in service for at least 40 years...

I will let you know how it works out...

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