Coolant Color

[EggHrbrGuy]

The Yanmar 2GM20F (2 cyl) has performed well in my '87 Tartan 28. Last fall I noticed the coolant contained small amounts of black crud. The boat yard diagnosis I hear most often is head gasket. Is it time to go in and see? Could it be something else?

[a64pilot]

Little almost granular black chunks are often nothing more than old hoses.
I've never seen a head gasket fail in a manner that lets black chunks into the coolant, but I guess it certainly could.
Assuming the coolant is old enough so it should be replaced anyway, I'd flush the system and if the hoses are very old or age unknown, I'd consider changing them, before I pulled the head.


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[EggHrbrGuy]

Thanks for comment. And if the crud was more liquid, what you you say?

[a64pilot]

I don't know, but I know checking for combustion gasses in coolant is simple and often done, it's really the best way to diagnose a blown headgasket. Call a couple of auto repair shops until you find one that does the test, then take some coolant to them.

Age and color of coolant, orange or green?


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[EggHrbrGuy]

Coolant Green. New in Spring '14
Will follow you suggestion. Thanks Again.

[GordMay]

Greetings and welcome aboard the CF, Jon.