"Roger Long" wrote in news:rhung.32956$W97.19823
@twister.nyroc.rr.com:

BTW do you know if the 2GM20(H) has the oil tube in the same place and
if the pump is the same configuration?



While we are talking about little Yanmars, let me make a point for all of
you to frequently check the damnable pickup tube in the coolant recovery
tank in indirectly-cooled Yanmars with heat exchanger. The tube is under
the cap, saving them money on having a proper BOTTOM outlet molded into
the tank plastic, itself, that cannot help but pickup any liquids in the
tank.

The tube under the cap starts to leak...or much worse yet falls off into
the tank....allowing, in either case, the heat exchanger to suck air as
it cools down, instead of liquid. The heat exchanger has no trouble when
it's heating putting liquid INTO the tank, but then sucks itself full of
air as it cools. This cycle continues until the heat exchanger is
DANGEROUSLY low on coolant, but when the owner inspects the level in the
tank, it looks like it has PLENTY of coolant from the high level in the
tank. As the level in the heat exchanger gets too low, the engine pukes
STEAM out into the coolant recovery tank and the engine overheats..or
worse.

Make a mark with a grease pencil of the stone cold coolant level after
inspecting the coolant level actually inside the heat exchanger's
pressure cap to make sure it's full. If that cold level ever RISES, your
pickup inside the tank is leaking or has fallen off.

Solution is a new piece of hose inside the cap that does NOT go all the
way to the bottom of the tank to pick up tank crap....5200 sealed to the
cap when it's totally dried because a hose clamp just pinches off the
cheap soft plastic the cap is made from. The 5200 makes a permanent bond
between hose and cap, I know. But, alas, caps are MUCH cheaper than
overheated diesel engines when the tube needs replacing 20 years from
now.

Unwilling to put up with this problem, I solved it permanently by
replacing the whole tank on one boat with a coolant tank out of a
car...properly made to withstand coolant pressure with a sealed cap. It
has the hose coming out the bottom fitting and will PRESSURE FILL the
heat exchanger as its pressure drops, not depend on it sucking fluid
through a straw like Yanmar. His tank was empty as it overheated blowing
steam into the Yanmar tank with the hose fallen off! The Yanmar tank
read FULL!

I'd love to survey the tanks in all the Yanmars in a large marina full of
sailboats to see how widespread the problem is. They should know better.