Just purchased 85 H34 boat and doing maintance on engine I drained coolant on fresh water system on Yanmar 3GMF and was going to flush sytem and replace with red anti freeze as recomended for longer life of coolant. I drained block at both drain ports and disconected hoses to hot water heater and just installed loop as I am replacing hoses as well. Drained out aproxx 1 1/2 gallons of old coolant and what looked like mud.Spec say capacity is 3.4 liter. Problem is when filling back up at heat exchanger could only get it to accept maybe 2 liters at the most. I drained a little more out of the block to make sure the block had water in it and then started engine thinking that once the pump started it would take more. Level remained full at filler. waited thinking once engine came up to temp thermostat would open and take remaining water. High temp alarm came on before water level ever went down. With infra red thermometer took reading at stat housing and showed 175- 185 well above where stat should be open. Thinking stat was slow I replaced with new and same situation. Even tested both stats in pan on stove and both started to open slowly at 71 c and fully open at 85c like specs say, one was more slow then the other though thinking there was something else I dove into system taking apart heat-x,water pump and removing all hoses which I planed on replacing anyways and never really found anything that I belive could be causing any problems other then a worn area on back plate of water pump that a previous impeller wore a goove that I am going to have built back up and some build up of mineral next to the seat of the bypass passage. Am I missing something ?Is this common for the alarm to go off while refilling the cooling system.Yanmar service manual doesnt address any special filling requirments.Has anyone else expiereinced this problem ? I am awaiting gaskets and hoses now before I reassemble.Think I will replace water pump as well while I have system apart. Any advice or expierience would be apreciated.
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Maybe Air...
.. I had something similar and it was air in the system that had to work through before it would take more coolant. You did use a recommended mix of coolant/water I assume. There can be a bunch of air in there. Run, get warm, check and add, etc. If that doesn't do it, pressure check it. Could be a head gasket. Good luck, Rick D.
.. I had something similar and it was air in the system that had to work through before it would take more coolant. You did use a recommended mix of coolant/water I assume. There can be a bunch of air in there. Run, get warm, check and add, etc. If that doesn't do it, pressure check it. Could be a head gasket. Good luck, Rick D.
could be in the hot water heater
When I change the anti-freeze I have to drain the anti-freeze out of the hot water heater. To refill the hot water heater you need to pour the anti-freeze down the hose until it comes out the other hose and reconnect to the engine block.
When I change the anti-freeze I have to drain the anti-freeze out of the hot water heater. To refill the hot water heater you need to pour the anti-freeze down the hose until it comes out the other hose and reconnect to the engine block.
Burping the Yanmar
Rick,when I changed my cooling hoses I ran into the same problem. I finally got the air out of it by starting the engine and loosening a hose on the top of the engine. It made a bit of a mess but I burped alot of air out of the system and was able to service the system with the correct amount of anti-freeze.
Rick,when I changed my cooling hoses I ran into the same problem. I finally got the air out of it by starting the engine and loosening a hose on the top of the engine. It made a bit of a mess but I burped alot of air out of the system and was able to service the system with the correct amount of anti-freeze.
Cooling System Bleed Valve
On our H-35 3GM30(F) we put a cooling system bleed valve to simplify bleeding the air out of the system after working on it or changing the coolant. The valve is placed at the highest point of the system which is above the thermostat cover. Parts are all bronze except for the valve which whas brass and spray painted with Yanmar matching paint. A plastic hose is attached to the valve and the free end is placed in a clear plastic drinking water bottle to collect any escaping fluid and to keep the engine room clean. The fittings are as light-weight as possible, except for the short pipe that attaches to the thermostat cover, and the assembly was kept as short as possible to keep all the mass down low in order to minimize fatigue failure caused by the diesel engine. The valve pin (handle) fell out last year so try to get a better valve or peen it to prevent this from hapening to you. I posted the piture elsewhere in the system (Hunter 35) with an explaination but it disappeared and the photo no longer shows up under Hunter 35 (although it did when it was posted). Phil - Help!
On our H-35 3GM30(F) we put a cooling system bleed valve to simplify bleeding the air out of the system after working on it or changing the coolant. The valve is placed at the highest point of the system which is above the thermostat cover. Parts are all bronze except for the valve which whas brass and spray painted with Yanmar matching paint. A plastic hose is attached to the valve and the free end is placed in a clear plastic drinking water bottle to collect any escaping fluid and to keep the engine room clean. The fittings are as light-weight as possible, except for the short pipe that attaches to the thermostat cover, and the assembly was kept as short as possible to keep all the mass down low in order to minimize fatigue failure caused by the diesel engine. The valve pin (handle) fell out last year so try to get a better valve or peen it to prevent this from hapening to you. I posted the piture elsewhere in the system (Hunter 35) with an explaination but it disappeared and the photo no longer shows up under Hunter 35 (although it did when it was posted). Phil - Help!
Cooling System Bleed Valve
On our H-35 3GM30(F) we put a cooling system bleed valve to simplify bleeding the air out of the system after working on it or changing the coolant. The valve is placed at the highest point of the system which is above the thermostat cover. Parts are all bronze except for the valve which whas brass and spray painted with Yanmar matching paint. A plastic hose is attached to the valve and the free end is placed in a clear plastic drinking water bottle to collect any escaping fluid and to keep the engine room clean. The fittings are as light-weight as possible, except for the short pipe that attaches to the thermostat cover, and the assembly was kept as short as possible to keep all the mass down low in order to minimize fatigue failure caused by the diesel engine. The valve pin (handle) fell out last year so try to get a better valve or peen it to prevent this from hapening to you. I posted the piture elsewhere in the system (Hunter 35) with an explaination but it disappeared and the photo no longer shows up under Hunter 35 (although it did when it was posted). Phil - Help!
On our H-35 3GM30(F) we put a cooling system bleed valve to simplify bleeding the air out of the system after working on it or changing the coolant. The valve is placed at the highest point of the system which is above the thermostat cover. Parts are all bronze except for the valve which whas brass and spray painted with Yanmar matching paint. A plastic hose is attached to the valve and the free end is placed in a clear plastic drinking water bottle to collect any escaping fluid and to keep the engine room clean. The fittings are as light-weight as possible, except for the short pipe that attaches to the thermostat cover, and the assembly was kept as short as possible to keep all the mass down low in order to minimize fatigue failure caused by the diesel engine. The valve pin (handle) fell out last year so try to get a better valve or peen it to prevent this from hapening to you. I posted the piture elsewhere in the system (Hunter 35) with an explaination but it disappeared and the photo no longer shows up under Hunter 35 (although it did when it was posted). Phil - Help!
vague memory..
I recall from a basic diesel class I took 2 years ago, the instructor mentioning that when you switch from the green to red anti freeze, all of the green must be flushed out completely prior to adding the red. If the 2 mix, it thickens and can clog in places. Has anyone else heard this? Bob Pilgrmi
I recall from a basic diesel class I took 2 years ago, the instructor mentioning that when you switch from the green to red anti freeze, all of the green must be flushed out completely prior to adding the red. If the 2 mix, it thickens and can clog in places. Has anyone else heard this? Bob Pilgrmi
Thanks for Info Problem solved
I solved problem of air being trapped above thermostat and in heat-x by drilling and tapping a 1/8 npt pipe thread into the flat area on top of the themostat cover housing in the thickend flat area next to mounting bolt. I inserted brass 1/8"npt x 1/4 flare fitting with 1/4 flare cap tp allow air bleed port. Worked great and 3GMF took all specified 3.4 liter capacity first time with no problems of air and over heating. Thanks to all who replied and I hope this can help someone else with 3GM
I solved problem of air being trapped above thermostat and in heat-x by drilling and tapping a 1/8 npt pipe thread into the flat area on top of the themostat cover housing in the thickend flat area next to mounting bolt. I inserted brass 1/8"npt x 1/4 flare fitting with 1/4 flare cap tp allow air bleed port. Worked great and 3GMF took all specified 3.4 liter capacity first time with no problems of air and over heating. Thanks to all who replied and I hope this can help someone else with 3GM
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