Coolant

Nov 20, 2013
19
hunter 38 sandusky, ohio
I need the add coolant to my motor and I have read on this site not mix colors of different coolants, is this true.
 
Mar 26, 2011
3,961
Corsair F-24 MK I Deale, MD
This could get very long winded. The simplest answer is to find out what it is, confirm that is acceptable for the engine, and then and match it. Yes, there are compatibility issues.

The problem with using color as an indicator is there is no accepted industry standard. It is legal to use any color dye that you like.

(I was in the industry as a manufacturer for >30 years)
 

Johnb

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Jan 22, 2008
1,505
Hunter 37-cutter Richmond CA
If it is urgent and you don't need very much I would just use plain distilled water, especially at this time of year.

When I first got my boat and did not know what was in there I found out what the correct anti freeze is, then double changed it. If you don't know what is in there now, or how long it has been, that may be a good thing to do.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
One of the first things I did when I purchased my boat was flush and change the unknown coolant in my auxiliary with the recommended Yanmar coolant. After six years I am doing it again using the very thorough testing and reporting conducted by Practical-Sailor, and poster #2 in particular.
 
Mar 26, 2011
3,961
Corsair F-24 MK I Deale, MD
Perhaps the most critical factor, FAR more important than brand, is seawater contamination. Coolants that are rated for 5-6 years in a truck are only rated for 1-2 years in a boat (I believe the Yanmar manual states this) because of the risk of a seawater leak (the condemning limit is about 1% seawater). I would use a chloride (not free chlorine--different) test kit annually.

Something like this:https://www.grainger.com/product/INDUSTRIAL-TEST-SYSTEMS-Test-Strips-3VEZ1
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
8,019
Hunter 430 Waveland, MS
is this true.
YES!
Two different chemicals with 2 different characteristics. Double check this...
Green/Yellow .... Ethylene glycol
Pink ... Polypropylene Glycol
Jim...
 
Mar 26, 2011
3,961
Corsair F-24 MK I Deale, MD
^^^ There are EG-based pink engine coolants, as well as green and blue PG-based winterizing products. NEVER go by color.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
TW: Because not all seawater has the same chloride concentration, is there a chloride contaminant value (rather than your 1% seawater limit) that would represent too much chloride in a coolant? 1% = 10,000ppm seems way high.