Slow water leak.

[jkishel]

If there is no coolant in the bilge and the engine oil level isn't rising, coolant has to be escaping into the exhaust. If the heat exchanger itself is sound, coolant is leaking through whatever seals exist between the heat exchanger and the coolant tank, or the tank is cracked and coolant is leaking into the exhaust manifold. Systematic use of a pressure tester will identify the leak, or just take everything apart and take a look.

[mestrezat]

There is nothing in my bilge, at least from the engine and my oil still looks like it should. I’m going to take a shot at the heat exchanger since I had problems with the innards if it getting clogged in the US Virgins a year plus ago(coolant failed and turned into a dense putty like substance). I don’t loose much coolant and there is no sign of it overheating so I’ll just keep topping it off till we haul out next month in Puerto Penasco, Mexico. I can get in another heat exchanger and bring it back with me a few months later.
Any other 5oughts would be appreciated.