Ford Lehman 120 raw water in coolant system

[Bmarler]

did you mention if the head was mag checked for cracks? or skimmed for flatness?
the one clean bore makes me think crack in the head, or failed head gasket. warped head can do it too.
i think you're getting cylinder pressure into the cooling system too, that's why the bubbling coolant tank.

 

[BruceK]

Not sure this is relevant to your issue but Lehmans can get blockage/restriction in the coolant passages around no.6 cylinder,furthest from the water pump. I think the cylinder can overheat due to low coolant flow and put the piston at risk. Clearing it requires some effort. Probably irrelevant here, but worth knowing. TF mechanical guys will understand the issue way better than me.

 

[Sweetypie]

did you mention if the head was mag checked for cracks? or skimmed for flatness?
the one clean bore makes me think crack in the head, or failed head gasket. warped head can do it too.
i think you're getting cylinder pressure into the cooling system too, that's why the bubbling coolant tank.

Definitely getting air in the cooling system, The head was pressure tested by a Mech shop, they tested it at at operating temp and cold.

 

[Sweetypie]

Not sure this is relevant to your issue but Lehmans can get blockage/restriction in the coolant passages around no.6 cylinder,furthest from the water pump. I think the cylinder can overheat due to low coolant flow and put the piston at risk. Clearing it requires some effort. Probably irrelevant here, but worth knowing. TF mechanical guys will understand the issue way better than me.

Ive read this a few times now, the 6th cylinder getting hot. Its cylinder 2 I believe.

Over Easter I plan to run a compression test, pressure rise the coolant system, check the Manifold and failing that Ill remove one injector at a time while pressurising the cooling system to 15psi while I inspect each cylinder with a camera.


I will keep this thread updated.

 

[AmericanVagrant]

Resurrecting this thread to add an update.

After having the heat exchanger repaired, I noticed down the line that I was still getting an overfilling coolant system. I chocked it up to a shoddy repair job and ordered/installed a new heat exchanger.

I again thought the issue was behind me but alas, it persisted. I was at a loss for what could be happening until a couple days ago when I had an epiphany, my water heater has a heat exchanger that feeds from that engine, that must be where it's coming from. To test my theory I looped the outlet and inlet back to itself, bypassing the water heater. I also put a cup beneath the water heater ports to check for water production.

Yesterday I went back to the boat, lo and behold water was slowly dripping from the ports on the water heater, and there was no evidence of water entering the coolant system.

So it seems the problem has been resolved. I'm embarrassed it took so long for me to figure it out... I assumed from the beginning that the excess water in my system was raw water, but apparently it was just fresh water from my tanks.

 

[rgano]

Good catch. Now, let us contemplate the possibility of injecting poisonous engine coolant into your potable water system. The radiator cap on the engine probably keeps your system at 12-16 PSI? IF your potable water system is not pressurized to over that value, well you get the point.

 

[AmericanVagrant]

Indeed, it seems that my water system was pressurized beyond the radiator cap, because it actually pushed water through it and out the overflow when at rest. Certainly a concerning possibility to keep in mind though.