For some time now our clarifier system for the Fresh hot
water from the
engine cooling circuit has not functioned.
The unit is installed a sole eight with the inlets to the
heat exchanger 2" above the sole level. The rad cap on the
coolant tank is 4" below the sole level.
There is no overflow reservoir in the system.
The
engine heat exchanger is new.
All the hoses as well as the Thermostat housing were replaced.
Coolant tank is new as well as rad cap,etc.
The operating engine temperature is 80C.
The engine never moves from this temperature after warming up no matter how hard I push the engine. I ran her at 2400
RPM for more than an hour heading to Southport and the needle never flickered.
Have flushed and tested the coolant lines from the engine to the hot
water tank.
Pushed water both ways through both hoses as well as the heat exchanger in the water tank so there a no check valves in the system.
Ensured Orifice for flow control on engine
heating circuit feeding the
calorifier system was clear with a small precision screwdriver well into the pipe.
Today started the engine at the
dock ran to warm up 80C at high idle to ensure thermostat is open.
Bled the coolant lines at the heat exchanger to ensure no air at this point as it is higher than the rad cap. Good pressure, and obviously fluid but impossible to tell if there was any flow.
Hoses were cool to the touch. Hoses in Engine compartment were warm and obviously hotter the closer to the engine. As soon as the hoses clear the engine compartment there is no obvious
heating effect and would indicate no flow.
Transmission in forward to load the engine ran up to 1600
RPM for 15 minutes. All conditions the same and I bled the hoses again at the water tank use to make sure. Continued to run the engine for another 15 minutes under load and no obvious visual changes.
It seems that the obvious cause would be no flow whether to a airlock or possibly a bad
cooling system
pump on the engine. However their is no obvious signs of a
water pump failure such as
overheating.
I do have a brand new coolant
water pump in spares but I am loathe to install it if there is nothing wrong with the old one.
Previous
repairs including replacing the
oil cooler in the water jacket due to
gasket failure. Apparently you have to been extremely careful when changing
fuel filters as any leaked
fuel will eat these old gaskets. Obviously a problem as they have upgraded the gaskets to metal with an embedded o ring. I believe that the problem started sometime around this
repair that was done at the same time as a new injection put was installed.
I read one thread somewhere that said that a separate coolant tank mounted higher than the highest point of the hot water tank was required when mounting the hot water tank higher than the engine. The factory rad cap was then installed on this new tank and a higher rated cap was installed on the original coolant tank. Unfortunately this does not explain why the system worked for the first 5 years we owned the
boat.
Thanks for the help.