I've just replaced the domestic hot water
heater which of course meant opening the coolant
circuit. The aux coolant
piping actually has 2 heat exchangers in the loop, one for the hot water
heater and one for a small cabin
radiator. They're plumbed in series.
I don't seem to be getting any flow through this loop, so I figure it's air locked. I pulled what I think is the return line to the engine
off at the engine
, and get no flow out (I also capped the engine port). Can someone confirm that the port on the thermostat housing is coolant out, and the adjacent port that connects on top of the line to the oil
cooler is coolant return? I also put a hand pump on the return line, and with the engine running tried pulling coolant. I did get some (and drained the expansion tank by doing it), but after removing the pump I still got no flow. Occasional dribbles, but nothing significant.
Am I on the right track, and just need to persist in pulling coolant through with the hand pump?
Also, can anyone confirm whether there's a zinc in the cooling
system on this engine? The manuals
seem to indicate only for turbocharged 4JH engines, but there is conflicting information in the service