The impossible to solve overheating problem

Tooljunkie said
Bypass hose is right below upper rad hose/ thermostat housing.
If heater core isnt flowing, its a big issue,a hose to bypass it is fine but it should never be blocked or restricted.

Great, I will check that the heater core is flowing and bypass it if necessary.
So the bypass fitting is the one below? You asked if it was the correct size? I have never changed it but I dont know if it is original. Can it be too small and restrict flow or?