for Marus I would say his is NOT the BO valve replacement???

I say this as he has far too long with perfect aircon, it sounds to like something is actually telling the valve to open, (so as Kaiser has suggested temperature sensor malfunction for instance...

Surely his aircon woudn'e 'good' for as long if the valve had started to deteriorate? once letting by, the valve cant repair itself, it is degenerative.

but what do I know My valve is defunct now lasted longer than most for an everyday use car.

Hope you get sorted Marcus.