I have noticed that after use there is pressure in the saildrive of our Bav 36. This happens if I remove the filler plug when the oil is warm, you can here the air coming out. I have often wondered why Volvo did not put in a breather like you get in most car gearboxes? Again I wondered if our “breather” had got blocked up! We only get a slight weep of oil from our saildrive.
However the good thing is that if there is pressure in the saildrive the seals at the bottom can’t be leaking! On the other hand I have thought that if you check the oil in the saildrive when it is hot and it then cools down it will produce a vacuum which could draw in some sea water past the seals! So now I only take out the filler plug when the saildrive is cold.
Is there a breather or do others experience this?
