Rig cooling sys for full flush, easy fill, and cheap pressure test??

Rig cooling sys for full flush, easy fill, and cheap pressure test??

Rigged my early US and Jap cars and trucks with the Prestone Flush kit that included "tees" to fit into heater return hose. Install a schrader valve in the screw cap for the "tee", hook up bicycle pump with a built in gauge and you have a cooling system pressure test that includes the radiator cap.

Advantages include:

Back flushing the system including the heater core,
Cheap but effective pressure tester,
Easy fill,
Incentive to change coolant more frequently.

We have had two previous overheats from clogged radiators, and current mystery that started with pionhole leak in gasket at the heater element on the side of the "throttle body", advanced through difficult bleeding, and is now sitting at good compression test, but coolant scum on the dip stick and in the oil fill cap.

Consider that first overheat was on Xmas eve 190 mi from home, two radiators down and one to go, etc etc, and frequent flush/fresh antifreeze routine seems like the way to go.

Question is where to insert the "tee" in the m20? Suspect the heater return hose, that weird one with the t that goes to the engine side of the thermostat housing and to the radiator expansion tank.