Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 18-07-2013, 07:23   #1
Registered User

Join Date: Aug 2012
Boat: Outremer 50
Posts: 165
Coolant Changes Color

We have two more or less new Volvo engines in our catamaran. (worked now 100 hours)
One is fine, the other one now shows a different color of the coolant (Type LR-25) which is normally blue-green. It has now changed to a dirty green (a bit brown). This engine has in the past repeatedly lost coolant and we think this was lost at the connections to the hot-water boiler which is connected to the engines coolant circuit. (We found coolant in the boilers bilge but now this is thought to be fixed)
What can be the reason for the different color? Can this be a leakage between hot water in the boiler and coolant? However our experience is that coolant and water separate from each other which should be visible in the engines coolant reservoir.

myocean is online now   Reply With Quote
Old 18-07-2013, 08:08   #2
Registered User
George P's Avatar

Join Date: Nov 2007
Location: Ft Lauderdale
Boat: Taswell 49
Posts: 80
Re: Coolant changes color

Just thinking out loud from a similar situation I had.
I would consider possible corrosion in the coolant system.
Or, did you add a different type of coolant when you topped off? Less so today but some coolants don't mix well and can react with canges in color and become thicker.

George P is offline   Reply With Quote
Old 18-07-2013, 08:52   #3
Registered User

Join Date: May 2009
Location: Vancouver, Wash.
Boat: no longer on my Cabo Rico 38 Sanderling
Posts: 1,794
Send a message via MSN to John A
Re: Coolant changes color

There is a possibility that, in overheating the engine, a pinhole has developed in the head gasket of one of the cylinders causing oil to intrude into the coolant.
John A is offline   Reply With Quote
Old 18-07-2013, 09:39   #4
Registered User

Join Date: Jul 2013
Posts: 6
Re: Coolant changes color

It could be a blown head gasket due to overheating ?
Change the coolant out and see if it returns.
How much coolant is it losing?
az_r2d1 is offline   Reply With Quote
Old 18-07-2013, 10:00   #5
Registered User
jstevens's Avatar

Join Date: May 2006
Location: On board Sarah, currently lying in Jacksonville, FL
Boat: Pearson, 424, 42', Sarah
Posts: 528
Images: 4
Re: Coolant changes color

Sounds a bit like oil in the coolant. How is your oil cooler plumbed? Is it cooled by raw water or the engine coolant? Does the oil show any sign of coolant? If any of the above is "Yes", then I'd change the oil cooler.

jstevens is offline   Reply With Quote
Old 18-07-2013, 11:44   #6
Registered User

Join Date: Jul 2012
Location: New England
Boat: Catalina 42 MKII
Posts: 123
Re: Coolant changes color

Oil in ethylene glycol/water coolant tends to emulsify and turn milky. Just to be sure, put some in a jar and shake vigorously – if it doesn’t emulsify, it’s probably not oil getting in the coolant. Also check the oil for coolant in the oil.

I would suspect corrosion, in which case the question would be whether it is occurring or residual from your previous problems. I would back flush the system thoroughly, fill with fresh coolant and then use a hydrometer to test & record the SG. Can you bypass your water heater and subsequently reconnect? That will allow you to see if it is coming from there. If it does reoccur, retest the SG to see if the coolant is being diluted with fresh water or maybe salt water from the heat exchanger, which is leading to corrosion.

Good luck!
Geoff54 is offline   Reply With Quote
Old 18-07-2013, 12:58   #7
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 15,062
Re: Coolant changes color

I also think this may be corrosion. Seen same story on Westerbeke gensets.

barnakiel is offline   Reply With Quote
Old 18-07-2013, 13:10   #8
Registered User

Join Date: Nov 2012
Location: Sapphire, Qld
Boat: 35 ft steel Boro
Posts: 95
Re: Coolant changes color

Combustion leak.
Get your hands on a colour change dye setup and it takes 1 minute to check to confirm at the radiator/ header tank.

Outwest34au is offline   Reply With Quote


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
Charts II: NGA - 2700 Charts cagney OpenCPN 1292 23-12-2013 08:46
Losing Coolant - Need Some Advice keao Engines and Propulsion Systems 14 06-12-2011 19:39
Coolant Leak Troubleshooting assfortress Engines and Propulsion Systems 13 26-10-2011 09:27
Glossy or Satin on Fishing Boat / Floor Color BigGreen Construction, Maintenance & Refit 0 05-09-2011 17:23

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:05.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.