Losing Coolant from Heat Exchanger

[sneuman]

I am having overheating problems with my Isuzu C240 diesel. It appears to be losing coolant from the heat exchanger at a fairly prodigous rate, but I see no evidence of the loss in the bilge. Once I discovered the problem, I was able to "baby" the engine along with no real problems by just adding more water every hour or so during operation.

Now, before this problem occurred, the engine belt (which also powers the heat exchanger pump) was broken and the engine overheated then before I shut it down (see previous post). So, I wonder if the thermostat being stuck could be involved here, although that wouldn't seem to explain the loss of fluid.

any thoughts would be appreciated.

[JiffyLube]

There could be a leak in the heat exchanger allowing coolant to escape to the raw water side, then out the exhaust with the raw water.