[C320-list] Thermostat for Perkins M-30: VERY hot fresh water at sink

[Louis Spitz via C320-list]

Hi folks,
Any thoughts on VERY hot water at galley sink, and replacing the Thermostat on a 1995 Perkins M-30? Could they be related? The engine runs HOT (c.205).
Thanks, Lou Spitz
Merry Chase
#195, 1995

[Christian via C320-list]

Lou,
I have a M30, and when at full load for about 30 mins, I peak at 182. I
would be getting nervous with it edging over 200. I suspect you have a
cooling issue somewhere, and yes I do think your very hot water at the
galley sink is related, as the engine heats your water too in the hot water
tank in addition to electrical heat. I have also replaced my coolant
thermostat, and my high heat thermostat, and can look up part numbers if
you need assistance (but might take me about 24 hours). Though I don't
think the high heat thermostat is your issue.

Things I would suspect in high heat are:
-check cooling system for any impeller fins or other debris
-are the tubes in your heat exchanger corroded or blocked?
-is your exhaust elbow clogged?
-Have you drained your coolant and introduced an air bubble in the system?

I would start there with those questions. You could have an issue with
your coolant thermostat not opening, but this is not likely. The main
failure reason of a toasted coolant thermostat is overheating the engine
and melting the wax in the thermostat (don't ask me how I know). The good
news is it's easy to test the functionality of the thermostat, you put it
in a pot of boiling water and see if it opens. The bad news is on the M30,
the coolant thermostat is behind your coolant pump, and a real headache to
get to (pump has to be removed, gaskets scraped, gaskets replaced, likely
seized bolts, etc). Again, it's unlikely your coolant thermostat is your
issue, and I wouldn't focus on that yet. Failure of that part is likely a
symptom of something else causing cooling issues on your engine, and
ultimately overheating the engine to the point of melting the wax in the
thermostat.

-Christian 1994 C320 "Canuck" #138 Monroe Harbor, Chicago, IL

[ART HARDEN via C320-list]

You are running hot! Check your heat exchanger and the lines to it. When was the last impeller replaced? You can get a mixing valve that will control the hot water temp but they are bulky in size.

Sent from my iPhone
Art Harden
Catalina 320 "Tortuga" E-62
937.885.9380 (o)
937.477.5544 (m)

> On Apr 10, 2024, at 9:57 AM, Louis Spitz via C320-list <c320...@lists.catalina320.com> wrote:
>
> Hi folks,

[ART HARDEN via C320-list]

Totally agree!

Sent from my iPhone
Art Harden
Catalina 320 "Tortuga" E-62
937.885.9380 (o)
937.477.5544 (m)

> On Apr 10, 2024, at 10:44 AM, Christian via C320-list <c320...@lists.catalina320.com> wrote:
>
> Lou,

[Dave Hupe via C320-list]

I've read the multiple answers to your question. A couple other comments:1. Obviously make sure the coolant level is up in your heat exchanger tank. If the coolant is not high enough, it doesn’t  cover the heat exchanger tube sufficiently for optimum heat transfer.2. Broken off impeller pieces can lodge in the front rubber cup at the front end of the heat exchanger tube.  There they can then block flow through the very small multiple tubes that run the length of the heat exchanger tube ... causing overheating. Here are replacement rubber cups and clamps for the ends of the heat exchanger tube https://www.parts4engines.com/perkins-perama-m30-heat-exchanger-end-caps/
3. Should you decide to replace your thermostat, I strongly suggest replacing your engine water pump (the original?) because you will need to completely remove the pump to replace the thermostat. My pump froze solid during my first year of boat ownership. The pump is not very expensive .... I bought here https://www.parts4engines.com/perkins-perama-m30-water-pump/  Here is the thermostat replacement kit https://www.parts4engines.com/perkins-perama-m30-thermostat-kit/ There is a thermostat retaining spring that you also should replace https://www.parts4engines.com/perkins-perama-m30-thermostat-retaining-spring/

Dave Hupe 
1994 C320 #32

Yahoo Mail: Search, Organize, Conquer

On Wed, Apr 10, 2024 at 9:57 AM, Louis Spitz via C320-list<c320...@lists.catalina320.com> wrote: Hi folks,