Yanmar 2GM20F

May 30, 2015
4
Hunter 30 Merrit island
I seem to be loosing coolant but see no leaks in side and no obvious coolant in the discharged water. Anybody have any "check this" advise?
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
I seem to be loosing coolant but see no leaks in side and no obvious coolant in the discharged water. Anybody have any "check this" advise?
check your oil and see if anything is not right about it ...it will look milky if you have a leak into the engine....also look around all the water system on the heat exchanger and fresh water pump hoses and all if you are loosing it you have to have a leak some where that should be visiable
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
Woodster is right first thing is to check the oil.

If you can not find any coolant in the boat then it is either burning it or it is going out the exhaust.

If there is a leak in the heat exchanger coolant can get into the raw water and go out through the exhaust system.

If there is a bad head gasket or cracked casting it can get burned in the engine, in that case it should produce some white exhaust smoke, maybe some smell.

You can buy a chemical test kit for the coolant to detect a bad gasket or cracked casting as the coolant will have combustion byproducts in it. The kits are inexpensive from NAPA etc.

A pressure test can also be done to try and detect the location of a leak.

I hope it is something simple.

Good luck, Bob
 
Jun 4, 2004
1,087
Mainship Piliot 34 Punta Gorda
On my 4j, there was a pin hole in the coolant jacket right at the exhaust. It is likely you have a leak somewhere in the coolant jacket or heat exchanger if you cannot see a leak anywhere else.
It is not that hard to take the heat exchanger apart to check this out.
 
May 30, 2015
4
Hunter 30 Merrit island
check your oil and see if anything is not right about it ...it will look milky if you have a leak into the engine....also look around all the water system on the heat exchanger and fresh water pump hoses and all if you are loosing it you have to have a leak some where that should be visiable
Ok thanks I'll check that again. I recently checked the level but didn't notice anything obvious, but wasn't looking at it that way. Thanks
 
May 30, 2015
4
Hunter 30 Merrit island
Thanks I did notice some light white smoke or what looked steam,,,, it dissipated very quickly. Guess I'll check into that test kit you mentioned.