"Aron Tvedt" wrote in
:

I have a yanmar 4lha htp inboard diesel engine, and have been trying
to cange the fresh cooling water, I wanted to add a new "long term
anti freeze".

My challenge is:
The capasity is 15 litres, but I am not able to fill more than 7-8
litres. I am afraid to run the engine hot, in case there is alot of
air in the engine main block.
The engine was cold when i filled fresh water on it, and I guess the
termostat was closed. There was also alot of dirt in the old cooling
water when I drained it. (stupid of me not to mesaure the amount I
drained!)

I have been guessing on 3 causes why I am not able to fill more than
half of the engines freshwater capasity:
1 The termostat is closed and airthight, and will not let me drain
half of the old cooling water.?
2 When the termostat is closed, it will not ventilate air out as I
fill the engine with new cooling water?, I am afraid there is big
airpockets where cooling is most needed.
3 Dirt from the old cooling water will not make me able to drain it
properly.?

Any surguestions?

Aron Tvedt, in the North of Norway



Although I have no direct knowledge of the Yanmar, I would expect the
thermostst to have a small bleed hole in it, this often has a "giggle
pin" in it to keep it free.

Unless your boat has keel/skin tank cooling 15l seems to be rather a lot
- could this be a mistake?

I would gently run the engine off load, with the filler cap off and watch
for any air to be expelled, topping up as required.

My feeling is that 7l is about right - but I stand to be corrected.

Tony Brooks