"Marc" wrote in message
...
Jeff: tip for the futu needing to pull the heat exchanger cores is
very rare. Just drop the end caps and use a 22 cal. bore brush.


Yes, I can appreciate that, and that's what I did on my last engine (a
Westerbeke). However, to really clean it you need to pull both end caps, and
on the Yanmar, the core just slides out after that. Actually, from my point of
view, the real hassle is draining the fluids - once that's done you might as
well do the complete job.

Also, it did seem like removing one end cap might compromise the seal at the
other end. And I was happy to get a good look at them, since they are
vulnerable to freezing and I spent half the winter wondering if I had done
enough to protect the engine from the deep freeze we just went through. I had
to fix two broken pipes in the basement this winter, so I've been a bit
apprehensive!

-jeff