Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-26-2017, 10:34 AM   #1
Guru
 
JDCAVE's Avatar
 
City: Lions Bay, BC
Country: Canada
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,226
Low Coolant Temperature

My son and I took the boat out for a steam-about yesterday. We were on the water for about 3 hours. Everything ran smoothly, with normal engine temperatures. On return I docked, and we spent 10 minutes or so "turning the boat" and playing with lines just before shut down. Just prior to shut down, I noticed the coolant temperature (gauge) was about 20 F below normal operating temperature. Additional information:

- Ford Lehman 135.
-about a 10 minute run up the harbour at 4.5 knots, which is about 1,000 rpm.
- water temperature is very cold right now--water temperature at Hope was 1.5-2.0 degrees C. I'd be surprised if the temperature at Steveston was more than 3-4 degrees or 37-39 degrees F. (Edit update: according to this, 3.9 C)
http://aquatic.pyr.ec.gc.ca/RealTimeBuoys/Default.aspx

Wondering if the thermostat is going wonky or is this "normal" given the cold water.
__________________
Advertisement

JDCAVE is offline   Reply With Quote
Old 02-26-2017, 10:56 AM   #2
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 7,619
Most thermostats have a little bypass flow, don't know if that is enough to pull the temp down. Do you have a cabin heater or water heater tied to the coolant loop? Neither of those are blocked when the thermostat is closed.

Ted
__________________

__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is online now   Reply With Quote
Old 02-26-2017, 11:15 AM   #3
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 5,357
Not unusual for a bit of leakage through thermostat. Sometimes this is intentional with a drilled hole or wiggle pin. It causes no problem, but when sea temp is super chilly, it will subcool the engine at dead idle.

As long as temps go to normal when you put a load on it, good to go.
Ski in NC is offline   Reply With Quote
Old 02-26-2017, 11:20 AM   #4
Guru
 
JDCAVE's Avatar
 
City: Lions Bay, BC
Country: Canada
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,226
Quote:
Originally Posted by O C Diver View Post
...Do you have a cabin heater or water heater tied to the coolant loop? Neither of those are blocked when the thermostat is closed.

Ted

Yes, I do, but it was not in use yesterday. The valve was in the mid line position but the pump was off, i.e. "Engine Heat" for the hydronic heat was off. FYI my young grandson was with us yesterday, and it was a bit of a challenge to keep him "inline" while I was doing things at the end of the day, so I didn't explore this more fully.

Jim
JDCAVE is offline   Reply With Quote
Old 02-26-2017, 11:49 AM   #5
Guru
 
C lectric's Avatar
 
City: B.C.
Country: Canada
Vessel Name: Island Pride
Vessel Model: xxxx
Join Date: Oct 2007
Posts: 2,472
Since the cooling showed only when idled and the seawater is cold don,t worry.

Unloaded diesels produce little heat at idle and wee bit of coolant bypassing the t.s. may do this.
Next run just watch it and be sure it comes up properly under load.

My different engine did the same if idled in winter.
C lectric is offline   Reply With Quote
Old 02-26-2017, 11:58 AM   #6
Guru
 
JDCAVE's Avatar
 
City: Lions Bay, BC
Country: Canada
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,226
Thanks people. I figured as much but I thought I'd throw this out there for opinions.
JDCAVE is offline   Reply With Quote
Old 02-26-2017, 12:18 PM   #7
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 16,093
I'd change the thermostat,

Check the new one before extraction and the old after.
Pretty easy job and inexpensive.

My Mitsu runs 180 - 190 (usually closser to 190) all the time and dos'nt take long to warm up. About 5min at idle. I have an old Nissan car (87) that warms up fast .. love it. My 13 Jetta w 32kmi takes much longer to heat up and I only have the heater output as a temp gauge .. don't like. The Nissan was even worse than the Jetta before I put a new thermostat in it.

If an old thermostat that is'nt bringing about a fast warm up or not keeping the temp up I think it should be replaced.
An engine running nice and warm will help keep the oil temp up and for FL's that's a plus.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 02-26-2017, 12:25 PM   #8
Veteran Member
 
City: Brownsville, WA
Country: USA
Join Date: Mar 2016
Posts: 71
I think that it is completely normal for a diesel to cool off when idling. The Perkins in our boat will drop 20 degrees when I'm not running at a cruising rpm, and the modern diesel in my pickup truck will cool from it's normal 200F to about 180-185 if it idles for a few minutes.
mgdavis is offline   Reply With Quote
Old 02-26-2017, 12:30 PM   #9
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 5,357
Eric- The mitsi and nissan are indirect injected, so lots more heat goes into the coolant at idle. The VW and Ford/Lehman are direct injected and put way less heat into the coolant at idle.

Replacing the tstat due to idle subcooling in cold water is likely a fool's errand. The tstats are often designed with a small bypass flow so sensor bulb gets exposed to actual coolant temp.

Also, the ford has sea water cooled oil, so coolant temp has little effect on oil temp.
Ski in NC is offline   Reply With Quote
Old 02-26-2017, 12:53 PM   #10
Senior Member
 
City: PNW
Country: United States
Vessel Name: EXILE
Vessel Model: HANS CHRISTIAN TRAWLER
Join Date: Jan 2016
Posts: 131
I also have a FL SP135. For the first 5 years of ownership operating temp was at 160. Since it was always at 160 I thought that was normal, not to mention that running cool seemed like an advantage. It was common for us to trail a plume of white smoke and sometimes leave a fuel sheen on the water following shutdown. Eventually I investigated and learned that almost all (if not all) 135s were shipped from the factory with 160 degree thermostats. Once I switched it out with a 180 degree (as is recommended) the steam and the sheen went away (not 100%). Engine is now operating at correct operating temp and is happy. I dont recall the engine temp dropping when at idle. Worthwile to replace and be sure the thermostat is a 180, IMHO.
petdoc4u is offline   Reply With Quote
Old 02-26-2017, 01:02 PM   #11
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 16,093
Quote:
Originally Posted by Ski in NC View Post
Eric- The mitsi and nissan are indirect injected, so lots more heat goes into the coolant at idle. The VW and Ford/Lehman are direct injected and put way less heat into the coolant at idle.

Replacing the tstat due to idle subcooling in cold water is likely a fool's errand. The tstats are often designed with a small bypass flow so sensor bulb gets exposed to actual coolant temp.

Also, the ford has sea water cooled oil, so coolant temp has little effect on oil temp.
OK Ski,
I was always amazed how my engine warms up so fast. Nice to know it was just something I just did'nt understand.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 02-26-2017, 02:26 PM   #12
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 7,921
Quote:
Originally Posted by C lectric View Post
Since the cooling showed only when idled and the seawater is cold don,t worry.

Unloaded diesels produce little heat at idle and wee bit of coolant bypassing the t.s. may do this.
Next run just watch it and be sure it comes up properly under load.

My different engine did the same if idled in winter.
At idle, in 78 degree water, our FL SP135 wont come up to temperature but does quickly under load.
Larry M is offline   Reply With Quote
Old 02-26-2017, 05:36 PM   #13
Guru
 
JDCAVE's Avatar
 
City: Lions Bay, BC
Country: Canada
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,226
Our normal running temperature is 180 F and once it's to temperature, it stays there. I just noticed the lower temperature yesterday and as mentioned the river temperature is 4 C. Southern Georgia Strait temperature at Halibut bank is 7 C.

We get a little blue smoke on startup. We get a little "steam" when it's cool but high humidity (fall period). No white smoke or "Seam yesterday although it was near freezing outside.
__________________

JDCAVE is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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





All times are GMT -5. The time now is 06:29 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×