Putting in a new heater core

[EdB]

Lucus,

Forgive me for not seeing that you don't have an AC truck.

Are you sure it is the core. It might have a mechanical
control valve. It could also be a loose connection on the
door that routes the air.

You can always unhook the hoses: run a garden hose to
the inlet; run the other hose over the fender; turn on the
water hose and check the flow.

We talked about this today. I have only changed out about
a half dozen on various vehicles. A friend, who has many
years experience, cannot remember every changing one
out because it was stopped up. It has always been because
they were leaking.

Just my thoughts.

Forgive me Longhorn.

EdB