Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 01-01-2017, 06:35   #1
Registered User

Join Date: Dec 2011
Location: Caribbean
Boat: Leopard 38
Posts: 101
Question to watertemp of a Diesel

My catamaran has 2 Westerbeke Diesel engines, each with 42 horses, maybe less cause they are old.
But they run ok and they sound ok, except on 1 an alarm goes on after more or less 10 minutes.
Both engines were not in use for about 6 months and my boat was in the water that time, when I cranked the Diesels for the first time again.
Now I realized that the water temperature of both engines thru the exhaust is quite different.
The water of the engine, which has the Alarm going on, is still cold after 10 minutes, basically has the same temp of the ocean water and is not getting warmer as the other engine has a Temp of 35-40, which I consider normal.
My suggestion would be, that the heat exchanger might be clogged?
I still haven't used Muriatic, what some people suggested Prior as I am still too afraid of.

Otherwise there's nothing wrong with the engine. All belts are good, it sounds good and solid, but Off course there must be a reason for the Alarm going on.
The engine is not overheating regarding my impression ... which might be wrong.
Thank you for your help.

ak5609 is offline   Reply With Quote
Old 01-01-2017, 08:08   #2
Registered User
boris's Avatar

Join Date: Sep 2007
Boat: warwick 44
Posts: 108
Re: Question to watertemp of a Diesel

I assume it is freshwater cooled?
I would start with a new thermostat

boris is offline   Reply With Quote
Old 01-01-2017, 08:41   #3
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,973
Re: Question to watertemp of a Diesel

First determine the reason for the alarm, I believe it can be either oil pressure or coolant temp.
Buy an IR point and shoot thermometer and use it to see if the engine is overheating.
If your heat exchanger is clogged, it is clogged on the fresh water side and that takes disassembly to clean. If it were clogged on the sea water side, then you would not get water flow out of the exhaust.

It does sound like a stuck closed thermostat though, easy to change. A stuck closed thermostat is essentially a clog.
a64pilot is offline   Reply With Quote
Old 01-01-2017, 08:48   #4
Senior Cruiser
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,785
Re: Question to watertemp of a Diesel

I doubt its a clog if the engine runs too cold! That would be just the opposite. I lean toward thermostat, although a bad one is pretty rare..... and it would have to be stuck wide open if the engine isn't overheating.
I second getting an IR thermometer and finding out if anything is really too hot or cold. One boat I had spent half way thru transiting the Caribe trying to diagnose an overheating issue. Turns out the sender was bad and the engine wasn't overheating at all. How does each engine compare if you test the block for heat with your hand?
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard

Cheechako is online now   Reply With Quote
Old 01-01-2017, 08:50   #5
Registered User
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,160
Re: Question to watertemp of a Diesel

Indeed it sounds like a thermostat stuck closed.

The freshwater side not circulating, getting hot and then the alarm.

The saltwater side flowing normally but not removing any heat.

Since the sender is in the freshwater cooling jackets it gets hot and trips. Yet the exhaust water is cool since it could not remove heat do to lack of flow in the exchanger.

I suppose the freshwater side of the exchanger could be plugged but that seems less likely than the usual salt water side.

Life begins at the waters edge.
four winds is online now   Reply With Quote

diesel, water

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Gas Station Diesel vs Marine Diesel Rocketman Engines and Propulsion Systems 75 08-05-2016 19:31
sigmar 190 diesel heater vs dickinson lofoten diesel heater donhodd Off Topic Forum 9 23-02-2015 11:22
Boat Diesel vs Truck Diesel In Training Engines and Propulsion Systems 37 26-11-2011 04:40
BMW diesel and black steel diesel fuel tanks johnpair Engines and Propulsion Systems 12 08-01-2009 14:30
diesel is diesel? Jack Long Engines and Propulsion Systems 12 03-09-2008 16:53

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 16:29.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.