Zonker is on to it, air is being sucked in when cooling from hot most likely in the vicinity of the fresh water pump if you have to burp the system there. Heat exchanger is acid cleaned and “rodded” every season.Īttached image shows “bleed valves” circled in red. Note: this has happened only one time on the way out?Įngine is not producing any unusual smoke at any time. Not losing fresh water coolant (bilge is dry). I have run a pressure test of the fresh water side and it is good. This is when the overheating will occur engine will start and run great but instead of running at 180-190 just over heats. On return, I generally start engine at the break wall to allow warm up. engine will be 180 to 190 water temperature, shut down system and sail. A typical scenario: fire up engine in slip–warm up engine and check systems-motor out of slip often motor out of harbor apx 30 min. This has happened several times but not all the time.
What has been happening is the fresh water side will create an air lock and the engine over heats. Heat exchanger is filled with a traditional radiator cap (new), cooled coolant runs to belt driven bronze impeller (bleed valve on body of pump),hose to engine block (front of block), exits block on top, at exit point there is an aftermarket hose and copper tube “loop” with a bleed valve the which is the very top of the system, enters the thermostat housing thus the block, exits the block via Yanmar standard fitting, hose back to top of the heat exchange just below fill cap. Fresh water side is a closed system with anti freeze/water as coolant. The salt water side is functioning very well. The cooling system is as follows: sea water enters vessel via thru hull-sea water strainer-manifold-engine mounted pump with “rubber” impeller-after market heat exchanger-mixing elbow. The engine is fresh water cooled (after market) and has never been cooled with salt water.
My Yanmar 3QM30H is overheating occasionally.
0 kommentar(er)
