Adding cabin/hot water heating to Yanmar 2GM

[Sailorman Ed]

I would like to add a hot water heating loop to my 2GM20 to use for adding some cabin heat. I see the 2 plugs on the thermostat housing which I assume will be a metric thread ?? I will need 7 feet of hose in both direction thinking to use a small automotive heater. Not looking for 100 degrees, just to make it bearable.

1. What is the thread size?
2. What is the nominal hose size? 1/2"?
3. Does the 2GM20 have enough "umph" to push thru 14 feet of hose?

Out of time so I need to be able to buy the connections locally, not order from a Yanmar supplier.
Thanks in advance. Ed

[the_alpine]

I believe yanmar makes a kit for these. Search for that and you should find the specs.

Possibly 1/2 inch BSP, but maybe 3/8npt.

[roverhi]

If the engine is raw water cooled or otherwise not a 2GMF but just a 2GM, you aren't going to get much heat out of the engine coolant. Saltwater cooled diesels need to run below, and most well below, 160 degrees to prevent salt deposits in the cooling system. Not enough heat to do much if anything with.

[westwinds]

Does the engine have a heat exchanger, that is a closed cooling system? If the engine is direct cooled by sea water, then it has a much lower temperature thermostat to keep calcium carbonate from precipitating on hot engine parts and causing cracks. The cooling water is at a low enough temperature that you will get very little heat. I do not like how salt water will eat the engine head and block from the inside out so I would go ahead and convert to a heat exchanger anyway if you do not have one. Check the engine first for how much metal is left. I remember reading about pulling a bolt for attachment of the exhaust manifold to the head and being able to measure how much longer the engine will last. Maybe this can be found with a good search engine.

[rbyham]

I just connected my 3qm30 raw water cooled to my hot water heater last week. The pump has plenty of umph to move the water and the temp while true runs lower at 140 is plenty to heat water and if I add a heater core and small fan would make the cabin toasty... probably something I will explore in January.