Yanmar 4JH-2E using coolant

[Tim R.]

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 engine

What is left are the following:
- Hot water heater leak
- Heat Exchanger leak
- Exhaust riser leak
- Hidden engine leak
- 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?

 

[kloudie1]

Suspect heatex tube or gasket .. I don't know of an easy way to check for coolant in seawater, but there may be someone who's worked that hre on the site, Tim.. Sorry to hear..
Maybe a LOT of bright green food dye in the coolant and look for it at the mixing elbow..

 

[richk]

similar problem...

Tim

Had a problem last year with coolant loss. Turns out hoses going to hot water heater were run through a stringer and diameter of hole in fibreglass was too small. Over time and with vibration a hole wore through one of the hoses. Coolant was dumping into hull liner. Really weird b/c it was just "disappearing"...not showing up in bilge or around engine.

We discovered it the hard way...about 30 miles from home, 100 degree day, no wind. Motored home with me tending the engine by dumping fresh water into overflow tank all the way (fortunately had plenty of that.) Planned to be home by 3 pm, got there at 11 pm. Dodging traffic in Chesapeake main channel south of Bay Bridge spans

Good luck.
Rich

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)

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

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

 

[alexco38]

Try the automotive trick, use a pressurizer tester pump. They should be available in any auto parts shop. Or else, connect up an air compressor (max 15 psi). To see where it leaks. They have auto radiator leak detector dye that show up under UV light.

 

[Tim R.]

Try the automotive trick, use a pressurizer tester pump. They should be available in any auto parts shop. Or else, connect up an air compressor (max 15 psi). To see where it leaks. They have auto radiator leak detector dye that show up under UV light.

I like the dye idea. I have looked into the pressure tester but am deferring that for now. I suspect it will show a leak but still not help me pinpoint it.

 

[Tim R.]

Tim

Had a problem last year with coolant loss. Turns out hoses going to hot water heater were run through a stringer and diameter of hole in fibreglass was too small. Over time and with vibration a hole wore through one of the hoses. Coolant was dumping into hull liner. Really weird b/c it was just "disappearing"...not showing up in bilge or around engine.

Good tip Rich. The PO did just replace the WH before we bought the boat. He has been very helpfull post sale and I am hoping he can provide some insight about when it started. The leak was apparent when we first bought the boat but was not as bad.

 

[RichH]

Try the automotive trick, use a pressurizer tester pump. They should be available in any auto parts shop. Or else, connect up an air compressor (max 15 psi). To see where it leaks. They have auto radiator leak detector dye that show up under UV light.

Alexco has it.
Get a radiator pressure tester, get some fluorescing dye for an auto shop that caters mechanics (not duffers). Charge the FW circuit with the dye and circulate for a few minutes then shut down, pressurize the FW circuit, wait, examine the lube/motor oil, the raw water discharge with 'black light' to make the fluorescent dye 'fluoresce' ... and then trace back to the source of the leak. Most times you can simply pressurize the FW circuit without the fluorescing dye and wait (hours) until you see a build up of fresh water in the oil, in the raw water discharge, in the oil, etc.