Vince's bus appears to be pumping air into the cooling system within a few seconds of firing up the engine.
The thermostats would have been closed, the pax heater gates are both closed, the air compressor has been shunted away from the cooling system, and the DDEC set a "high coolant level" code (16) and the water level substantially increased in the surge tank.
Also sez he can hear air bubbles 'boiling' up into the surge tank following cold shut down. My bus doesn't do that even when shut down hot...only noise is oil dripping back into the crankcase.
IHMO, the engine has been bled satisfactorily. I've got an identical bus and it bleeds within a few seconds. Some engine combos may not, but these NJT systems are easy to bleed.
For a time, as I understand, Vince would start the bus and it would shut down due to either high or low coolant within a very short period...long before heat expansion would increase the water column.
The DDEC isn't likely related to the problem. Nor the water pump or thermostats. Water pump isn't doing any great thing anyway until the thermostats open. Although, a DDEC sensor fault could be the problem. Ex NJTs are famous for setting bogus "Low Coolant" codes.
My bus is still in 'winter storage'...what Vince needs is someone to crank an MC9 and see what the water level does. I've never paid any attention to what the sight glass does when the engine is initially started...it may surge up and down. May not. I set it and forget it.
I'm with RickB....the problem sounds like a cracked head.
No water in the oil. That may change.
And maybe no problem at all...? Or maybe a faulty high water sensor?
The bus seems to be functioning for now, and my thoughts would be drive it and see what happens. Unless coolant becomes obvious in the oil or the engine begins to miss--or overheats, nothing will be worse for the wear.
If the bus does begin to miss, an infra-red tem gun will ID the cylinder.
Vince, make sure the dash water temp guage is working correctly. The dash sender is the automotive looking temp sender screwed into the pax side thermostat housing. One wire sender. Ground the wire and the guage should move to "hot" when the ignition is "on." The engine doesn't have to be running to verify that the guage works. It it doesn't move, check the wiring at the guage, if patent, change the guage (remember that it is a 24V guage). If it moves, but doesn't read when hooked up to the sender, replace the sender.
The DDEC will shut down on "Hot Coolant," "Hot or Low Oil Pressure," and "Low or High Coolant." It will shut down with bogus sender signals too.
See if you can read all of the codes. On a DDEC I, the codes are lost if the DDEC fuses are pulled or the batteries disconnected. Turning off the battery master will not depower the DDEC ECM. Keep in mind that some of the DDEC wiring is always "hot" if working on the bus wiring. This is true for the 'Distributor' (engine unit), and the ATEC and DDEC ECMs.
Whaddaya think bus peoples?
Good luck, JR