Yanmar 4JH-2E using coolant

[treilley]

Here is what I know:

- Engine runs very well with ample power at all rpms
- I have to top off the overflow tank after every 4 hours of motoring
- No overheating(yet)
- No coolant in oil(crack in block)
- No pressure in heat exchanger when running the engine with the cap removed(bad head gasket)
- No apparent leaks under the engine

What is left are the following:
- Hot water heater leak
- Heat Exchanger leak
- Exhaust riser leak
- hidden leak into bilge
- Something I am missing?

Any of these should have coolant in the bilge, hot water system or the exhaust. Does anyone know of a way to test for coolant(trace amounts) in water?

[dabnis]

Assuming there is water in the bilge, I have read that dogs will drink it because it is sweet? If you don't want to taste bilge water there may be some sort of dye that will show up under an ultra violet light?

Dabnis

[dabnis]

Originally Posted by dabnis

Assuming there is water in the bilge, I have read that dogs will drink it because it is sweet? If you don't want to taste bilge water there may be some sort of dye that will show up under an ultra violet light?

Dabnis

Ultra violet leak detector: Black Light World - Fluorescent Tracer Dyes

Dabnis

[jrd22]

I think I would try to isolate where the leak is by disconnecting the lines to the hot water heater. If you are still using coolant then it's got to be engine. You said that there was no pressure in the overflow with the cap off while running but wouldn't it be more apparent if you left the cap on so the pressure built up? There is a way to check if exhaust gases are present in the coolant, an automotive parts store should have it.

[Beersmith]

I have the same engine and had the same problem. Turned out to be the hot water heater.