Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 28-05-2016, 14:47   #1
Registered User

Join Date: Apr 2012
Boat: Catalac 12 M
Posts: 14
Black Radiator Water

My 1985 Onan GenSet with a Cummings engine turns the fresh water in the cooling system black. I have flushed it 5 times and the water still is not clear. It appears to be very fine particles suspended in the water that will not fall out. I noticed this last year and again this year when I changed the coolant. The engine coolant level stays constant all year and the engine is used all year as we are full time crusiers. Any ideas?
__________________

__________________
DrDelmas is offline   Reply With Quote
Old 28-05-2016, 15:27   #2
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,593
Re: Black Radiator Water

If it's not oi and "particles" suggests not. My next guess would be very active corrosion and I'd suspect you are about to deal with a significant issue if not addressed.
__________________

__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 28-05-2016, 15:45   #3
Senior Cruiser
 
senormechanico's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 5,825
Re: Black Radiator Water

Possibly combustion products entering coolant through cylinder head/gasket/block crack?

Hopefully not.
__________________
Memento,homo, quia pulvis es, et in pulverem reverteris.
senormechanico is offline   Reply With Quote
Old 28-05-2016, 16:39   #4
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: Black Radiator Water

How about rotting hoses?
__________________
Guy is offline   Reply With Quote
Old 29-05-2016, 10:16   #5
Registered User

Join Date: Oct 2011
Posts: 2,432
Re: Black Radiator Water

Get one of the automotive radiator testers and see if excess pressure (even a little excess) is building up in your system. You may find you have a small head gasket leak allowing gasses into your cooling system. Small leaks usually get bigger. Good Luck. Grant.
__________________
gjordan is offline   Reply With Quote
Old 30-05-2016, 03:28   #6
Registered User

Join Date: Nov 2007
Location: Brisbane
Boat: Lightwave 45 under construction .Previous self built Roberts 36
Posts: 186
Re: Black Radiator Water

Hi there is lot of info on the automotive forums....typically indicates hose failure. If oil was getting in through a damaged head gasket, then the water is likely to be a creamy colour rather than black. Are there other symptoms ? Among other things, white exhaust smoke can indicate a defective head gasket.
__________________
Glenn C is offline   Reply With Quote
Old 30-05-2016, 09:37   #7
Registered User

Join Date: Apr 2012
Boat: Catalac 12 M
Posts: 14
Re: Black Radiator Water

Thanks for the advice, will pressure test but suspect the hoses. I have no idea how old they are.
__________________

__________________
DrDelmas is offline   Reply With Quote
Reply

Tags
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
Radiator Hose used as Stuffing Box Hose johnsgj Engines and Propulsion Systems 35 14-01-2015 00:03
Radiator cap stuck in Westerbeke 4-91 marvinjansen50 Plumbing Systems and Fixtures 4 30-08-2014 16:36
Perkins 4-108 "radiator" cap question SvenG Engines and Propulsion Systems 13 07-09-2013 19:16
Heat Exchanger Cleaning and Testing at Radiator shop zboss Engines and Propulsion Systems 1 22-06-2013 21:05
Radiator Flush Chemicals - Safe in Marine Heat Exchangers? Dockhead Engines and Propulsion Systems 6 07-07-2012 16:46



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.