On the firewall, under the hood, you will find the inlet and outlet hoses.
I don't know about the outside diameter of the hoses but, the outside diameter of the heater core inlet and outlet tubes are 3/4" (inlet) and 5/8" (outlet).
Upper and lower radiator, inlet and outlet heater core, bypass,Upper and lower radiator, inlet and outlet heater core, bypass,
Remove both heater hoses from inlet & outlet of heater core. Connect these hoses together.
Couple inlet and outlet hoses together
There are two hoses that connect to the heater core, and they are located next to the brake master cylinder, on the driver side of the van. I believe the bottom hose is the inlet and the top hose is the outlet. Good Luck, Greg
2 - inlet & outlet
join the inlet and outlet hoses together.
It depends on the vehicle you have. In many cases (but not all) the inlet hose is smaller than the outlet hose.
Disconnect heater core inlet and outlet hoses - couple them together
Simple, take the inlet and outlet hoses going to and from the heater core and connect them together.
No it will not, it will just back flush the heater core and clean it out.