"Garland Gray" wrote in
:

IIRC you had some issues with the coolant overflow tank supplied by
Yanmar. I think it had to do with the overflow tube entering the tank
through the top rather than the bottom. Did you find a better
alternative ?

I think I'm having a similar problem. Coolant is transferring to the
tank, and little returns.




In order to draw coolant that was put in the tank when the engine heated up
back into the heat exchanger when it cools down, there must be a suction
strong enough to LIFT the coolant in the tank up the internal tube
connected to the cap. This suction is the root of the problem as it
happens very slowly each time the engine cools, so if there is the tiniest
air leak anywhere from the pressure cap on the heat exchanger to the end of
the tube inside submerged, we hope, in overflow coolant, the airleak will
never allow the coolant to recharge the heat exchanger for next
time...effectively, after a few cycles, emptying the heat exhanger!

It's a really stupid design just bound to fail at the worst possible
moment....when the boat is in heavy weather, pitching and yawing violently,
causing the coolant in the tank to flog around, loosing the stupid hose
inside that's NOT hose clamped to the cap....doesn't even have a
barb....and the hose falls into the tank so only air can be sucked out of
the tank from that point.....


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Larry
You can tell there's very intelligent life in the Universe
because none of them have ever tried to contact us.....