Yanmar emgine coolant replacement

phennessey

phennessey

.
Dec 15, 2012
22
Catalina 309 Boston
Just drained my 2006 Yanmar 3YM20. There was a fair amount of rust in the drained coolant so I continued to run fresh clean water through the system until no more rust was evident. The manual states that this model would take 4.2 quarts or slightly more than a gallon. My engine only took about half that ! I 'm not sure why that is but I suspect there's lots of sediment as well as some clogging as well. Any advice on next steps would be greatly appreciated. I started the engine and ran it at about 1500 rpm for
About 5 mins. Engine to rose to about 140*F which is normal. Any thoughts as to why the engine took only about half of what the manual stated? Thanks
 
Ralph Johnstone

Ralph Johnstone

.
Jan 4, 2006
6,473
Hunter 310 West Vancouver, B.C.
Just to keep track of what comes out vs. what's returned, I always drain into a graduated jug and then replace the same volume of AF as what I removed. I know I'm not getting everything, everytime from the block, heat exchanger, and domestic hot water heater so I like to replace the coolant every two years to make sure I'm keeping up with the anti-corrosion agents in the AF.

I notice you say that you only got to 140 after five minutes. Any problem in geting to a running temperature of 170 when loaded ?
 
jsalley

jsalley

.
Mar 20, 2007
500
Catalina 355 Kilmarnock, VA
Did you drain the block? There's a drain tap on the starboard rear of the block, aft of the oil filter. It can also be reached from the aft berth. You need to remove the radiator-type cap from the top of the heat exchanger to get it to drain completely. My engine had a short (443) 850-3798length of plastic tubing on the tap to help direct and catch the AF.
 
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