I recently acquired an old Shannon 28 with a Yanmar
3GM30F YEU. The only access to refill the fresh water coolant
is through the reservoir (see pic). There is a fitting where the pressure cap should be, that connects to the overflow reservoir.
Questions are as follows.
1) for this engine
, are there 3 coolant
drains, one on each side of the engine
for fresh water
and a third drain on port starboard side, for raw water
2) I have a bypass fresh water coolant loop to a 6 L Raritan
hot water heater. The tubing from the heater to the fresh water pump has no drains or purge valves. How do I refill this enginge and purge air from the system and the loop to the water heater?
My thought would be to unscrew the fitting where the fresh water fill cap should be, to refill directly, though there is not much access to the top of the enginge, after draining out the coolant from the system and probably detaching the hoses to the hot water heater to empty the coolant from the water heater loop.
3) how do I refill the system and purge any air from it, given the absence of purge valves?