Reply
 
Thread Tools Display Modes
 
Old 05-12-2012, 03:21 PM   #1
Veteran Member
 
Join Date: Dec 2011
Posts: 49
Losing coolant

Hi Guys-
Got an Isuzu C-240 (four cylinder diesel). When run at idle (600rpm) for 20 minutes or so,
the temperature holds steady at 140, the cooling system does NOT
pressurize, and it loses about a half gallon of coolant.
The bilge is dry and the engine starts and runs easy. Exhaust appears
to be clean water with no color or odor.
What to do?

Thanks-
Eeber
__________________
Advertisement

Eeber is offline   Reply With Quote
Old 05-12-2012, 03:27 PM   #2
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
I'm clueless, but John Deere says my 4045D shouldn't run at idle for longer than five minutes.

__________________

__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 05-12-2012, 04:08 PM   #3
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
Quote:
Originally Posted by Eeber View Post
Hi Guys-
Got an Isuzu C-240 (four cylinder diesel). When run at idle (600rpm) for 20 minutes or so,
the temperature holds steady at 140, the cooling system does NOT
pressurize, and it loses about a half gallon of coolant.
The bilge is dry and the engine starts and runs easy. Exhaust appears
to be clean water with no color or odor.
What to do?

Thanks-
Eeber
If the coolant is not leaking, it's going out through the exhaust. The cheapest possibility is a blown head gasket. It gets more expensive from there.

If you just filled it and it only did this once, there could have been an air pocket. If you haven't messed with it and it just started loosing coolant, and keeps on loosing coolant, you're going to need a mechanic or a service manual, a good set of tools, and some serious mechanical ability.
rwidman is offline   Reply With Quote
Old 05-12-2012, 04:24 PM   #4
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Mark,
That's a good point but not an OMG issue.

I'd be concerned about the very low coolant temp. My Mitsu warms up quickly to almost 190. Every time. I suspect that your coolant is very likely going from the coolant side of the heat exchanger to the sea water side. I'd check the heat exchanger. And 140 degrees warmed up temp is too cool. Is it a Klassen Engine?
Nomad Willy is online now   Reply With Quote
Old 05-12-2012, 04:57 PM   #5
Veteran Member
 
Join Date: Dec 2011
Posts: 49
Quote:
Originally Posted by manyboats View Post
Mark,
And 140 degrees warmed up temp is too cool. Is it a Klassen Engine?

Haven't seen "Klassen" anywhere on it.

Maybe a different thermostat will fix the low temp?

There is a new exhaust elbow. Would that be a clue that maybe the
exchanger is bad? Either way, with that much coolant loss, I'll pull
the heat exchanger to begin with. Good guess?

Thanks Gentleman-
Eeber
Eeber is offline   Reply With Quote
Old 05-12-2012, 05:03 PM   #6
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
Quote:
Originally Posted by manyboats View Post
Mark,
............. I suspect that your coolant is very likely going from the coolant side of the heat exchanger to the sea water side.
That's another possibility.
rwidman is offline   Reply With Quote
Old 05-12-2012, 05:16 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: 13,712
Eeber,
No ...the exhaust is sea water.

Yes ...a thermostat should fix the temp. Check your coolant cap (like a radiator cap). I run a 13 lb cap and about 185 degrees. If you only have a 5 pound cap you should probably run a 170 thermostat.

I still think it's the heat exchanger.
Nomad Willy is online now   Reply With Quote
Old 05-12-2012, 05:25 PM   #8
Guru
 
swampu's Avatar


 
City: Biloxi, MS
Country: USA
Vessel Name: Cajun Rose
Vessel Model: Biloxi Lugger
Join Date: Jul 2011
Posts: 1,145
What happens after 20 minutes? Does it over heat? I know it's a stupid question but just covering the bases. I was loosing about that much and than it would over heat. I replaced the cap to 15lb cap with a good spring and problem solved.
swampu is offline   Reply With Quote
Old 05-12-2012, 05:44 PM   #9
Veteran Member
 
Join Date: Dec 2011
Posts: 49
Quote:
Originally Posted by swampu View Post
What happens after 20 minutes? Does it over heat?

No it does not overheat.

Thanks for the tip on pressure caps.
Eeber
Eeber is offline   Reply With Quote
Old 05-12-2012, 06:07 PM   #10
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,903
If you are loosing coolant...and it's not in the bilge or the oil...my guess it's going out through the heat exchanger into the exhaust...not too many places it can go.
psneeld is online now   Reply With Quote
Old 05-12-2012, 06:16 PM   #11
Veteran Member
 
Join Date: Dec 2011
Posts: 49
Quote:
Originally Posted by psneeld View Post
If you are loosing coolant...and it's not in the bilge or the oil...my guess it's going out through the heat exchanger into the exhaust...not too many places it can go.

I'll remove it and send it to a radiator shop for testing/repair.
It looks like it bolts all the way through from the outside?

Thank-you-
Eeber
Eeber is offline   Reply With Quote
Old 05-12-2012, 07:02 PM   #12
Veteran Member
 
Join Date: Dec 2011
Posts: 49
One other question if I may;
What effect, if any, would the fact that the coolant system is not
currently pressurized, have on the operating temperature?

Thank-you-
Eeber
Eeber is offline   Reply With Quote
Old 05-12-2012, 07:45 PM   #13
Guru
 
swampu's Avatar


 
City: Biloxi, MS
Country: USA
Vessel Name: Cajun Rose
Vessel Model: Biloxi Lugger
Join Date: Jul 2011
Posts: 1,145
Nothing if the temp never gets up above 140. PV=nRT
If volume is constant, which it's not your loosing volume. Coolant is not pressurized. And your temperature is constant at 140. n is a constant and r is a value given for particular liquids. I would say if your temperature is constant and your unit doesn't overheat than the higher your temperature is the more volume you loose. If you let the unit run long enough you will develop more pressure.
swampu is offline   Reply With Quote
Old 05-13-2012, 06:51 AM   #14
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,529
I would suspect an air lock somewhere in the system.

At 140 there is no use for a pressure cap, so leave it off and keep filling if the coolant level drops.

Long ideling sucks for your ( or any) engine , as does 140F, which will not get rid of combustion products in the oil.

Go for a ride , in gear, and see what the temps become underway.

FF
FF is offline   Reply With Quote
Old 05-13-2012, 07:45 AM   #15
Guru
 
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 6,371
Sorry to say Swampu but the Ideal Gas Law does not apply in eeber's case, his is not a closed gaseous/liquid system due to a liquid leak somewhere that occurs below temperatures where a vapor phase can be established. Think steam engines for a better application.


Eeber (if not an air lock) if you have a TX heat exchanger this would be a good time to check and clean it too. Potential leak areas are:
  • Head gasket or cracked head
  • Exhaust manifold
  • HX
  • Turbo if JWAC
  • Bad plumbing
Also, double check/test your oil for coolant. As suggested get a pro on these engines. Start with boatdiesel.
sunchaser is offline   Reply With Quote
Old 05-13-2012, 07:51 AM   #16
Guru
 
swampu's Avatar


 
City: Biloxi, MS
Country: USA
Vessel Name: Cajun Rose
Vessel Model: Biloxi Lugger
Join Date: Jul 2011
Posts: 1,145
Quote:
Originally Posted by sunchaser View Post
Sorry to say Swampu but the Ideal Gas Law does not apply in eeber's case
That is probably why it took 7 years to get a 4 year degree
swampu is offline   Reply With Quote
Old 05-13-2012, 09:36 AM   #17
Veteran Member
 
Join Date: Dec 2011
Posts: 49
Quote:
Originally Posted by sunchaser View Post
if you have a TX heat exchanger this would be a good time to check and clean it too.

What's a TX heat exchanger?

Thank-you
Eeber
Eeber is offline   Reply With Quote
Old 05-13-2012, 12:25 PM   #18
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
I do'nt see how it can be an airlock as pressure would rise to some degree.
Nomad Willy is online now   Reply With Quote
Old 05-13-2012, 01:49 PM   #19
Scraping Paint
 
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
Quote:
Originally Posted by Eeber View Post
When run at idle (600rpm) for 20 minutes or so,
the temperature holds steady at 140, the cooling system does NOT
pressurize, and it loses about a half gallon of coolant.

How do you know it does not pressurize, is there a pressure gauge on the system?

Does the rate of loss continue if you run it longer than 20 minutes? For example, if you ran it for 40 minutes would you lose a gallon?

If it runs longer, does the temperature increase?

Before spending a lot of money on mechanics to remove heat exchangers and send them out for testing, I would get a car parts store radiator pressure tester and check it while not running. I would put a flourescent dye tracer in the coolant and view the exhaust overboard with a UV light as well as check all the plumbing associated with the cooling system.*

If you have a coolant loop in your potable water heater, check the hot water as well.

* You probably won't get anything out the exhaust with the engine shut down so after doing the pressure check with dye, start the engine and watch the overboard with the light. Do this in the dark for best results.

If you see dye glowing, disconnect the transmission cooler inlet and see if the source is upstream (the engine itself or the heat exchanger) or not. If not, then reconnect the inlet and disconnect the outlet from the transmission cooler and check it after pressurizing, dye in that location with none at the inlet shows the cooler is leaking.
RickB is offline   Reply With Quote
Old 05-13-2012, 03:15 PM   #20
Senior Member
 
capt jerry's Avatar
 
Join Date: Oct 2007
Posts: 321
rick has the right way to do it, it could be the tranny cooler,oil cooler,or the hot water heater if it is heated by the engine. take his advice it good.
__________________

capt jerry is offline   Reply With Quote
Reply

Thread Tools
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 09:22 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012