[C320-list] Engine water temp problem

[Rick Sulewski]

Graeme,
I recall that some aging antifreeze over time could tilt toward becoming
acidic and even attack certain metals, seals or gaskets and that activity
could introduce some gunk into the engine cooling system and increase engine
temps. Given the small cost of a sender, I replaced mine before I discovered
that I had pinched the lead and that was causing the gauge to peg. The new
sender began to read an even lower temp once I discovered the cause of my
gauge pegging. 
To reduce cooling system issues I try to replace/refresh a portion of the
antifreeze every three years. 
Rick

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Graeme Clark
Sent: Saturday, April 08, 2017 1:19 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Engine water temp problem

Rick
Thanks for the tip but the gauge does "climb" as the engine warms? it
doesn't go straight to max reading!
I haven't yet had a chance to troubleshoot further. Possibly tomorrow if
it's fine weather as I want to start by cleaning up all contacts. 
My gut feeling is the most likely reason for a problem is because of
something I did rather than a random failure whilst the boat was laid up
over winter  - it would be odd for a temp sender to fail when it sits in an
unused engine for six months, surely!
All options will be explored though!
Graeme

Sent from mobile: please excuse typos etc.!


> On 8 Apr 2017, at 15:34, Rick Sulewski <rsulewski at bex.net> wrote:
> 
> Graeme,
> If you did anything with your wiring over layup you could have a sensor
lead  grounding and pegging your gauge. For example, several years ago I had
my valve cover off to adjust my Westerbeke valves and inadvertently pinched
the temp sensor lead when the cover was reinstalled and that caused my temp
gauge to peg.
> Rick
> 
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Onat Dogruer
> Sent: Friday, April 07, 2017 11:17 AM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Engine water temp problem
> 
> On a side note, I just replaced the 18 year-old Johnson water pump (with
same model Johnson pump) on our Yanmar and the temperature is not going
above 160. It used to hover around 170F. I wonder if they improved somehow
the efficiency. 
> -OnatKittiwake #546, 1998
> 
>      From: Allan S Field <allan.field at verizon.net>
> To: C320-List at Catalina320.com
> Sent: Thursday, April 6, 2017 2:20 PM
> Subject: Re: [C320-list] Engine water temp problem
> 
> Our boat was about 10 years old when the temp sender unit failed.  A
replacement was ordered from Yanmar for about $20 US 7 years ago and
installed in about 10 minutes.  Problem fixed.
> 
> Allan S. Field
> Sea Shadow - C387, #103
> Columbia, MD
> 
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Graeme Clark
> Sent: Thursday, April 6, 2017 1:14 PM
> To: C320-List at Catalina320.com
> Subject: [C320-list] Engine water temp problem
> 
> First time I run the engine this year the water temp gauge goes off the
clock!
> I therefore bought a point and shoot laser thermometer and sure enough the
engine temp ( measured where the sensor is and also at fuel injector points)
is around 170f whereas gauge is showing 280-290f
> 
> So it's the sensor or the gauge. How do I test the sensor.  There is only
a single terminal so I'm guessing the resistance changes with temp. Does
anyone know what resistance should be at say, 170f ?
> 
> Or is there a simple way to test gauge
> 
> I did have the instrument panel out this winter to repair the lid so it
could be a dodgy connection I guess. I'll check everything again but any
more info would be handy as I'm stuck on boat with limited internet access!
> 
> Graeme
> #366, 1996 running Yanmar 3GM30F
> 
> 
> Sent from mobile: please excuse typos etc.!
> 
> 
> 
> 
> 
>