[C38] Overheating issue

[Mark Lewis]

Had overheating also.  Make sure water exiting exhaust thru hull, so u know
impeller is good. Also learned engine will overheat if the thermostat is
removed due to a bypass circuit (counter intuitive).
On Jul 10, 2014 9:36 PM, "Michael de lisle" <krazymiked at gmail.com> wrote:

> So I am completely stumped and need your input.
>
> This all started when my boat overheated and boiled off all the water in
> the manifold filling the cabin with white smoke (steam). We got her back to
> the dock under sail and my initial thought was a plugged heat exchanger. On
> the trip back I had pulled the thermostat to check it and gave it the boil
> test where everything worked as it should. As a precaution I left the
> thermostat out to let the engine run cool but it was still getting hot.
>
>  When we got back to the dock and with the fresh water circuit still in
> tack I opened the bleed off valves and noticed that the fresh water I had
> added to the manifold was not mixing with the coolant at the bottom bleed
> off valve.
>
> When I got down inside I found the valves for the hot water tank strapped
> to the heat exchanger (HX) and the bracket that supports the HX snapped off
> at the bolts and the whole mess sitting atop the transmission housing.
>
> I pulled all the hoses and the HX plus hot water tank plumbing out and
> found that the HX was actually looking pretty good. I flushed the engine
> with the hoses removed and it was flowing through all the ports with out a
> problem. I soaked the HX overnight anyways in a mix of muriatic acid and
> water since I had it out and have yet to reinstall.
>
> When explaining all of this to my local mechanic he suggested that the
> likely problem was the fresh water pump mounted on the front of the engine.
> Tonight I pulled the the fresh water pump from the block and found
> absolutely no issues with it. No wobbles, no wear, no goop or corrosion.
>
> So whats the problem???
>
> Tomorrow I am taking the HX and the pump to the shop to have them
> inspected. I am also going to double check the block with a hose to make
> sure all the ports are open and free flowing. Once I get a new bracket
> fabricated I am reinstalling everything with new hoses.
>
> Has anyone got any advice as  where else I should maybe check before
> putting everything back together?
>
> I have not ruled out an air lock from low coolant in the system but won't
> know if that was the issue until reinstalling everything.
>
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