I have a problem I can’t figure out…
I took off the heat exchanger and cleaned it with barnacle buster. tested if
it for pressure leaks and it passed with flying colors. the impeller has about 30 hours on it and is relativity new. put in and tested a new thermostat. I flushed out old antifreeze with garden hose, then with distilled water twice. first time with a flushing agent. after the second time I added quality antifreeze to the system.
it started over heating.
thinking must have air lock, I loosened the thermostat housing to let some air out, didn’t work, then I unscrewed the temperature sender from the engine, nothing came out, keep loosing it until the whole thing came out with the engine running, hoping to bleed air out of the system, but nothing came out only steam. shouldn’t cooling fluid be coming from the sender if its out ? I am lost as to what to do next
ps. plenty of water is coming from the exhaust.
Had a similar problem with a different engine. I think that if you have good raw water flow and the heat exchanger is in good shape then the problem is on the coolant side. Air lock is one possibly—when you open the coolant cap do you see coolant? If you remove the sender and pour water into the coolant area, does water/coolant come out (and that stuff is toxic to pets and wildlife so be careful). When my engine had air lock I had to fill then run the engine for 30 seconds and repeat five times before I got all the air out.
Given that you recently removed and replace the heat exchanger, my guess is air lock. The only remaining possibility is that the thermostat is failing to open.
Got it to around 180-200, filled again, the started and stop a few times, it seems to work ok
Wrong !!! I took it out and it overheated and blew the head gasket, guess I didn’t fix it after all. A mechanic is looking at it and will come up with a price to fix it, should I fix it or get a remanufactured engine or buy a new one. Bummed