We recently purchased a Cape Dory 27 with a fresh BetaMarine 14 (WOC: K26460; Engine No. BA6558; Marinized May 2011) engine with a Technodrive Twin Disk TMC 40 P transmission both with 140 hours as of yesterday. The service history is unknown to us, so we are performing all plausible service items to establish a baseline and see how things are looking.
Short story: We opened the coolant drain pet**** to drain all of the coolant, and nothing came out... bone dry. Removed the pet**** screw, and still nothing. How do we drain all of the coolant on this engine? How do we fix the pet**** so it drains coolant?
Long story: We pumped as much coolant out of the heat exchanger as we could prior to trying to remove the tube stack for cleaning and inspection. We decided to do this because the zinc anode had corroded and broken off from the plug that it's mounted to, and we figured we'd better see if electrolysis had become an issue in the heat exchanger. We couldn't get the tube stack out because the hi-rise exhaust blocks it from sliding far enough back to extract it (removed the heat wrapping, pipe still blocks tube stack. Will come back after it when we have some replacement gaskets for the exhaust pipe). So, cleaned in situ as much as possible, shined light through each tube to verify that they weren't blocked, reassembled, and carried on. At this point, we opened the coolant drain pet**** and got nothing (fill cap was off the engine). After replacing the raw water impeller and cleaning out the raw water strainer, we decided to put the old coolant back in the system until we could figure out how to drain and flush.
Somewhat related photos attached - last one is what the manual suggests is the coolant drain pet****, we think!
Thanks,
TJ Minski
-- Edited by TJ Minski on Sunday 29th of May 2016 11:04:16 AM
I suspect that the coolant has been a bit rich and has coagulated in the cooling passages. This is not unusual and all you need to do is use a piece of soft electrical wire (#12 or 14) and after you have removed the T, you can jiggle the wire through the valve and elbow into the the cooling passages which should cause the coolant to run out. I have attached a photo illustrating this.
It is a simple matter to remove the exhaust elbow and to allow enough space to service the tube stack. Don't forget to replace the exhaust gasket and the heat exchanger O rings when you do this.
Thanks for this info and the warm welcome. The picture really helps visualize what will be going on as we try to set the coolant free from the engine. We'll give it a go.
So, follow-up question, should we be concerned about the coagulated coolant clogging up all of the internal passages? How do we go about flushing the coolant properly before adding new coolant? Just several cycles of distilled water in the engine, run for a bit, cool for a bit, drain, repeat? Any specially formulated additives we should use to flush?
We'll certainly be ordering some more parts, including several exhaust pipe gaskets. The tube stack will get a thorough cleaning in the fall.
I assume that you use a 50% anti freeze mixture with water. If this is so it may be a little rich for your climate or it has been left in a bit longer than the manufacturer advises.
When you unplug the blockage, once the coolant begins to flow let it drain. When it stops refit the T handle tap and refill the cooling system with 40% anti freeze and distilled water. As the engine goes through its cycles of hot and cold with normal use, the rest of the old anti freeze will be absorbed. Leave this in for the rest of the season and drain and replace the coolant with 50% mixture for the winter lay up. Please make sure that the anti freeze that you use is compatible with aluminium.
Success. Thanks Stanley. It took some digging around with the wire, some zip ties, some solder, and a small screw driver. We finally got a little dribble going, closed everything up, fired up the engine to heat up and pressurize the cooling system, then shut down and let the pressure push the coolant out until it had cleared enough of the precipitate to get a good flow. We were able to get all of the coolant out and replace with 2.25 L of new stuff, at a 40/60 coolant/water ratio. We're in the South Puget Sound, so it's not very warm up here, mostly. We'll repeat in October or November with a 50/50 ratio.
