My review of the usual steps for coolant change in the 5432 suggests:
Either run engine till thermostat open or remove thermostat.
Drain coolant from two petcocks, under alternator and at inaccessible rear of manifold.
Drain coolant at heat exchanger.
Run distilled water through block. Refill with coolant and troubleshoot for air locks. Expect to hand-fill thermostat hoses and maybe water heater hoses.
Here's the question:
Why not just run the engine with a petcock open, and as the coolant level drains keep refilling the old with new until you figure the old coolant is displaced and mostly replaced?
There must be something wrong with this idea, which would presumably not introduce air and change most of the coolant (while wasting a few gallons).
Either run engine till thermostat open or remove thermostat.
Drain coolant from two petcocks, under alternator and at inaccessible rear of manifold.
Drain coolant at heat exchanger.
Run distilled water through block. Refill with coolant and troubleshoot for air locks. Expect to hand-fill thermostat hoses and maybe water heater hoses.
Here's the question:
Why not just run the engine with a petcock open, and as the coolant level drains keep refilling the old with new until you figure the old coolant is displaced and mostly replaced?
There must be something wrong with this idea, which would presumably not introduce air and change most of the coolant (while wasting a few gallons).