Big heating-problems with 400ci on PLymouth Satellite

[Johnpat]

You started by saying customer said it was ok
before you did the work.
Why did they bring it in for work ??????
Seems there must have been some problems
when they brought it to you ???

 

[Dennis H]

Thermostat and shroud required.

 

[Shorthorse]

According to Duratherm Fliuds, water boils at 252 degrees F at 16psi. A 50% mixture boils at 267 degrees F at 16psi. That's why you hear all that noise and see overflow when the engine is shut off because water in a block always gets hotter when an engine is shut off. More importantly, you are probably boiling the water or damn close to it on your test runs. If that's the case, no wonder it won't recover. Once the cap has lifted the pressure temporarily decreases to 0 psi (boiling point, 212 degrees). Also, an overfilled radiator will release water simply because the water volume increases as temperature increases. If the cap doesn't seal back, the radiator will not re-pressurize.
Most everything above is just "results", not causes. I've been following this thread and it is very perplexing. It appears you have tried almost every logical thing and then some.
I have to agree with RJS about the water pump housing. At least try to find out what you have.
Air flow and coolant flow, it sure sounds simple enough but it's obviously not that simple.
I'm pulling for you. Good luck and please keep us posted

 

[Dennis H]

Agree with above, but basics not covered if i read this right. Last run was with no shroud and no t stat. All bets off. When upgrading, i avoid anything with high flo, ultra, super etc in the name. especially when talking water pumps etc. the basic Ma Mopar ingredients keep mine cool now that they are working.