[C38] Overheating issue

Fri Jul 11 15:16:20 EDT 2014

I vote for a coolant leak from a hose or somewhere else that resulted in
loss of fluid and overheating. After you refilled, it is likely that an air
bubble is blocking the circulation. Every time I flush the system, I have a
very hard time getting the air out. Usually many attempts of bleeding and
revving the motor are needed to clear it. I turn the motor off before
severe overheating takes place and let it cool, and then try again, during
this process. If you are getting raw water thru the heat exchanger and it
has been working for awhile, I doubt that this is causing your problem.
Good Luck.

Mike Norcross
Escape 318

On Fri, Jul 11, 2014 at 2:59 PM, littlebreeze at comcast.net <
littlebreeze at comcast.net> wrote:

> Michael, when my water heater is hooked up my boat runs hot, about 210,
> and cooks all the food in the ice box.  However, when I disconnect the
> water heater the engine runs at 180 as it should and doesn't effect the ice
> box.  I too have heard these engines run on the hot side, but I doubt you
> had problems all these years and are just now bringing it up.  So what
> changed.  Is you inline water intake filter partially plugged?  Is your
> under boat intake partially plugged.  Do you have a freeze plug leaking.
>  Is there another leak in the cooling system allowing the engine coolant to
> leak out.  If the closed system has a leak, the coolant boils at a lower
> temperature.
>
> Just a few thoughts
> Kerry Grimes
> Little Breeze, 139
>
> Loyalty above all else, except Honor.
>
>
>
> ----- Reply message -----
> From: "Max Soto" <maxsoto at gmail.com>
> To: "Catalina 38 Listserve" <listserve at catalina38.org>
> Subject: [C38] Overheating issue
> Date: Fri, Jul 11, 2014 10:20
>
>
> Michael, I don't have a water heater on my boat. As a fact, you might
> disconnect it while you find the problem.  You'll have less thing to check
> for..
> With a blown gasket you won't immediately see oil mixing with water.  It
> takes a while ( if a cylinder is joined with a coolant conduit) , unless
> the coolant and oil conduits get joined.
>
>
> Max Soto
> +506-8312-1367
> Alajuela, Costa Rica
>
> On 11/07/2014, at 11:12, Michael de lisle <krazymiked at gmail.com> wrote:
>
> Thank you for your input guys. My boat is hull #240 and has the Universal
> M3 (5424) diesel. I just installed a brand new raw water pump two months
> ago and had plenty of flow in the exhaust exiting the boat. I thought about
> a blown head gasket but there is nothing mixing with the oil to indicate
> that this is the issue. As for the bracket, I am taking it to a very
> reputable welding/fabrication shop here and having them fab up a new one
> that will be a bit beefier. And I can not afford a new exchanger just yet
> but will be upgrading to the three inch when I do. How is your plumbing for
> the hot water tank mounted? Mine was strapped to the exchanger with a
> couple of radiator hose clamps.
>
> On Fri, Jul 11, 2014 at 10:02 AM, Max Soto <maxsoto at gmail.com> wrote:
>
>> The heat exchanger is definitely not good enough for the 5424, but if it
>> has been working for some years, and suddenly the engine overheats like
>> that, that is weird.
>> The engine could run perfectly without a thermostat. Mine has been like
>> that for more than twelve years.
>> An air bubble might be the issue, but is weird that it develops out of
>> the sudden, since it usually happens when you are filling an empty engine
>> with coolant.
>> You haven't mentioned anything about the raw water system.. Is it working
>> as it should???
>> A blown head gasket should be taken in consideration.  A compression test
>> will tell the truth.  And also, a  very bad coolant cap failure might have
>> some effect like that
>>
>> Just my two cents!
>> Max Soto
>> +506-8312-1367
>> Alajuela, Costa Rica
>>
>> > On 10/07/2014, at 22:36, 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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