HarryMann

Can anyone detail exactly where that vent is best placed, or whether the Phase II's have it already? Not having either, but looking at 2.5 II I'd like to have that information..

Thanks for that, makes sense now. So is it now becoming almost fact, that these issues are more at the heart of head gasket and intermittent overheating problem s than the head gasket design itself, if that makes sense as a question?

Is that coolant or air? Can't see any problem with the former....

Sound eminently sensible to me... its the sort of test an aviatione ngineer would dream up, just can't afford not to have every precaution taken for longevity. They never just throw these things into an aircraft, always re-engineer them, downrate them useually and pay particular attention to the actual installation - as with say, Kubota static engines, they won't sell then to anybody without exhaustive installation/reliability trials... reputation! With the new Gen Subie's proclivity to cooling system bleeding difficulties, does this expalin the 2.5's growing reputation for head gasket problems?