Yanmar diesel coolingwater problem

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On our 470  with a Yanmar diesel engine 4JH3-TCE we experienced a strange phenomen: After one day aboard I checked the engine room and saw the expansion tank overspilling and the water slowly dripping into the bilge. I emptied it to the "Full"-markline and started the engine. Everything looked fine but after 1 hour the tank was overspilling again. It was the normal green antifreeze liquid inside and I emptied it again although the engine was stopped by then since another hour. I had to repeat this procedure about three times until it came to my mind to switch off the pump of the freshwater system. Now the water level stayed at the Full-mark. 

 I always thought that the freshwater-cooling system of the diesel is a closed circuit and has got nothing to do with the freshwater pressure system of the boat. Of course there is the hotwater boiler included in this circuit but this only is a tube running to and away with a heating spiral in between which is mounted inside the boiler. So there is no contact with the cooling water.

Can anybody explain me this?

Edited by tobo - 06 February 2012 at 15:43

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tobo Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 01 February 2006 Location: Switzerland Status: Offline Points: 263	Post Options Post Reply Quote tobo Report Post Thanks(0) Quote Reply Topic: Yanmar diesel coolingwater problem Posted: 06 February 2012 at 15:42
	On our 470 with a Yanmar diesel engine 4JH3-TCE we experienced a strange phenomen: After one day aboard I checked the engine room and saw the expansion tank overspilling and the water slowly dripping into the bilge. I emptied it to the "Full"-markline and started the engine. Everything looked fine but after 1 hour the tank was overspilling again. It was the normal green antifreeze liquid inside and I emptied it again although the engine was stopped by then since another hour. I had to repeat this procedure about three times until it came to my mind to switch off the pump of the freshwater system. Now the water level stayed at the Full-mark. I always thought that the freshwater-cooling system of the diesel is a closed circuit and has got nothing to do with the freshwater pressure system of the boat. Of course there is the hotwater boiler included in this circuit but this only is a tube running to and away with a heating spiral in between which is mounted inside the boiler. So there is no contact with the cooling water. Can anybody explain me this? Edited by tobo - 06 February 2012 at 15:43
	Thomi

Sailingjack Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 30 March 2011 Location: Finland Status: Offline Points: 121	Post Options Post Reply Quote Sailingjack Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 16:18
	Warning! Your water heater may be corroded causing cooling fluid to mix with fresh water. Having fresh water pump on, it pushes water to cooling system. Swithing the pump off will let the poisonous cooling fluid to enter fresh water system. I hope there is another, not a severe cause for the overflow you are experiencing.
	Hanse 400#803 s/y Saara

Peter-Blake Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral of the Fleet Joined: 04 March 2008 Status: Offline Points: 2471	Post Options Post Reply Quote Peter-Blake Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 16:28
	Hmmmmm, first of all i would check if someone mixed the hoses when the boat was winterized. As i do not think that this happened it could only be the the spiral of the Coolantwater, which runs through the warm water heater has been correded inside the warm water heater. So the pressure of the fresh water pump pumps the water into your motor. A small leak is enough for this!
	Blake 370

Peter-Blake Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral of the Fleet Joined: 04 March 2008 Status: Offline Points: 2471	Post Options Post Reply Quote Peter-Blake Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 16:35
	Sorry, posted at the same time. BTW: one thing i am wondering also: Your warm water heater is positioned above the expansion tank. I remember that i read somewhere that this is not correct. It should be always positioned lower than the expansion tank, thats what i remember. You may check this aswell! Maybe i am wrong... But i am sure this is not related to your problem
	Blake 370

Sailingjack Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 30 March 2011 Location: Finland Status: Offline Points: 121	Post Options Post Reply Quote Sailingjack Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 16:39
	Hei Thomi, My earlier post was send away (by me) before I had finished my text. Clumsy me. So... Is your water boiler made of stainless steel? There has been some discussions about water boilers Hanse installed earlier. According to these posts, the boilers rust and start to leak. If there is a hole in the heating coil inside the boiler then the two systems merge. Depending of the pressure difference: water pump vs. pressurised cooling system, fresh water system or engine cooling system will flood. For starters I would check the water boiler using an air compressor.
	Hanse 400#803 s/y Saara

Wild Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 18 March 2010 Location: Turkey-Greece Status: Offline Points: 937	Post Options Post Reply Quote Wild Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 17:10
	Hello Tobo, If there is a small leak in the heating spiral (our double wall for some brands)of the hotwaterboiler and the freschwater is under pressure it will enter slowly in to the cooling ciruit because the pressure in the freschwatercircuit is higher than in the cooling circuit. is this the original location of the hotwatertank by Hanse 470 or did you change this yourselve? IMO the expansiontank must be at the highest place of the cooling ciruit(normal engine +15CM), and de boiler must by lower than this point.In this position there are problems to get the air out of the cooling circuit in the boiler hey will not work very well and air in the boilerspiral will give extra corrosion problems=leaks
	Wild and Wet Belgium 545e#268

Windsurfer Members Profile Send Private Message Find Members Posts Add to Buddy List Rear Admiral Joined: 07 April 2010 Status: Offline Points: 614	Post Options Post Reply Quote Windsurfer Report Post Thanks(0) Quote Reply Posted: 06 February 2012 at 17:22
	I think the procedure would be relatively simple...the first thing you do is checking the hose conection at boiler inlets and outlets and making sure everything is correct...then you simply open the engine cooling water filling cap and start the fresh water pump...if the liquid overflows - your boiler needs to be replaced...after replacing it and checking everything you will need to thoroughly clean the fresh water circuit around the boat and then change the antifreeze in the engine as I belive the mixture now would freeze much sooner... Good luck...I hope someone just misconnected the hoses....
	Hanse 320 #079 White hull, tiller, short keel and rudder, standard North sails, Sparcraft rig

keith goodall Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 25 October 2005 Location: New Zealand Status: Offline Points: 89	Post Options Post Reply Quote keith goodall Report Post Thanks(0) Quote Reply Posted: 13 February 2012 at 07:50
	Tobo we had exactly the same problem a few years back. It seemed that corrosion inside the boiler enabled fresh water to move between the engine heat exchanger and the boiler. We noticed it when fresh water containing coolant appeared in the engine compartment. Fortunately for us the boiler ( an Isotemp) was still under warranty and the Italian suppliers replaced it without difficulty. I cannot see that you have a problem with hose connections as you have had the boat a few years without this problem previously.
	Keith Goodall Savarna 531#36 www.sailblogs.com/member/savarna

tobo Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 01 February 2006 Location: Switzerland Status: Offline Points: 263	Post Options Post Reply Quote tobo Report Post Thanks(0) Quote Reply Posted: 16 February 2012 at 09:56
	Dear Keith The shipyard confirmed the speculation: the heating spiral is rusted. Do you think Isotemp will replace it under warrany after 5 years, how old was yours? 5 years is a too short lifetime anyway. A friend suspected it could be stray current and there should be an anode inside. What do your think? Pics will follow. Edited by tobo - 16 February 2012 at 09:56
	Thomi

Wild Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 18 March 2010 Location: Turkey-Greece Status: Offline Points: 937	Post Options Post Reply Quote Wild Report Post Thanks(0) Quote Reply Posted: 16 February 2012 at 11:15
	Hey Thomi, 5 years lifetime is indead not very long for a Stainless Steel AISI 316 like Indel-Webasto(isotherm) claims in there catalog. IMO a anode is not necessary in a SS boiler, only in a steel boiler protectect with a coating, and in connection with a circiut of a higher resitant metal(in a boat there are only PVC and rubber tubes connected to the boiler so he is isolated).The only reason why the boiler is leaking after such a short time is a chemical reaction between the cooling water and air inside the heating coil I think. By the way, in our boat (build 2010) there is a Qiuck B3 boiler(AISI 316) installed by Hanse. Wild Edited by Wild - 16 February 2012 at 11:19
	Wild and Wet Belgium 545e#268



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