I have filled my D2-40 from new and there is no need to bleed air from the block. If you look closely, the cooling
system is very well designed with no airlocks and my engine
is installed dead horizontal.
Fill from the small plastic header tank in place and let the coolant
find its way into the block. It takes a few minutes. From memory, there wasn't even a level drop in this tank when I started the engine
, so don't overfill to allow for it.
As long as you don't have a weird installation
with a saildrive
and the front of the engine lower than the back, it should be a complete non-event.