[C38] Overheating issue

Charles Finn charles at finn.ws
Sun Jul 13 08:11:32 EDT 2014


As you look at the 5423 engine, on the lower right side you will see a 
coolant line.  I have put an in-line tee with a small threaded nipple 
there that allows me to fill engine coolant from the bottom of the 
engine up.  When I am done, I put a pipe end cap on the nipple. I use 
one of those pumps from Harbor Freight that costs less than $10.  I have 
not had a bubble problem since!
I have just returned from a couple weeks out on my boat.  Two of the 
boats we sailed with had inpellor failures!  Everyone "claims" they 
replaced them regularly, but after seeing one of them...  I have to wonder.
Another problem we are having on the Great Lakes is Zebra Mussels.  
Those nasties get up on the heat exchanger as eggs in the water stream 
and hatch.  This is a real problem if like me, you leave the boat for a 
week or two and give them time to grow. I am pretty much resigned to 
cleaning out my 3 inch exchanger on a yearly basis.

Chuck Finn
Mighty Quinn  #114
Great Lakes


On 7/11/2014 3:16 PM, Michael Norcross wrote:
> 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 
> <mailto:littlebreeze at comcast.net> <littlebreeze at comcast.net 
> <mailto: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 <mailto:maxsoto at gmail.com>>
>     To: "Catalina 38 Listserve" <listserve at catalina38.org
>     <mailto: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 <tel:%2B506-8312-1367>
>     Alajuela, Costa Rica
>
>     On 11/07/2014, at 11:12, Michael de lisle <krazymiked at gmail.com
>     <mailto: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
>>     <mailto: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 <tel:%2B506-8312-1367>
>>         Alajuela, Costa Rica
>>
>>         > On 10/07/2014, at 22:36, Michael de lisle
>>         <krazymiked at gmail.com <mailto: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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