[C320-list] Coolant system flush techniques?

[swampcreek42]

Mine is a Euro as well but I believe they're all the same as far as this goes. 2 AF drains, one by the oil filter and one by the dipstick. The one on the heat exchanger is raw water. I drain from both drains and then remove the water heater hoses and blow them out. I fill the water heater hoses and then fill the motor until the AF runs out of the water heater hose connection at the motor, I then connect the water heater hoses and finish filling the motor. I run the motor until the t-stat opens and then 10 or 15 minutes more, stop engine and drain. Give the motor time to cool then start over again. I first drained the green stuff, flushed with straight distilled water then flushed with Prestone radiator cleaner flowed by 5 additional flushing. One point to remember, if the motor is relatively warm and you have fresh cool water in it for another flush the cooler water will prevent the t-stat from opening fully and you'll get a high temp situation, if this happens shut it down and wait for the block and water temperature to even out.
Bruce Hunter Nauti Time #719 


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-------- Original message --------
From: Jeff Hare <Catalina at thehares.com> 
Date: 07/30/2015  9:57 AM  (GMT-05:00) 
To: C320-List at Catalina320.com 
Subject: [C320-list] Coolant system flush techniques? 

First:  Yanmar 3GM30F  (European)

Seeing as our boat is out of service for a while, it's a good time to do a serious cooling system flush.  I see and feel some slime coating the surfaces where the antifreeze touches.  I've used the "drain a little/add a little" approach since we got the boat.

There are two AF drain ports I know about.  One on each side of the engine block.  One only drains down a little bit of antifreeze whereas the other is located lower on the block and removes quite a bit more.  So that takes care of draining some of it by gravity.   I don't know if the hot water heater system is drained or partially drained by this but I suspect not. 

So what's the best way you know to flush the slime out of the system in preparation for new antifreeze? 

-Jeff Hare
#809

PS:  I'm starting to collect quite a bit of used antifreeze in my garage... Having a hard time finding a place to take it here in NH.


-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of swampcreek42
Sent: Thursday, July 30, 2015 7:08 AM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] What antifreeze/coolant?


    
After flush #7 the water was completely clear. I replaced the thermostat and hose running from the t-stat to the heat exchanger, then being it was 10:00PM I went home. After work I'll go down and replace the other 3 hoses. I'm still deciding on weather to fill the engine with it's new coolant today since it won't be the recomended full 24 hours cure time on the thin coating of Permatex Ultra Black that I used on the t-stat gasket until 10:00PM tonight. Bruce Hunter Nauti Time #719 


Sent from my Verizon Wireless 4G LTE smartphone