1976 Ford E-Series Van heater hose routing

It goes on Top

it really doesn't matter which one goes where. the coolant flows through it either way

Ok so with a new heater core, new water pump, new thermostat, and new blower motor, what could cause me to have low heat output? The new blower motor doesn't seem to be doing a lot, but the air comes out normal Luke warm even with the engine at normal operating temp.

if youre still experiencing cool temps check the blend door ops. if that's ok then grab the heater lines at operating temp and compare them with the top radiator hose. they should be close. if the heater line is cooler then your water pump isn't pumping enough because heater lines come directly off the waterpump. or the lines are restricted, check for a restrictor in the heater lines put there by ford in some models. itll look like a lump in the hose and be hard when squeezed. you can remove that. if still in doubt take off the easiest line on the heater core and start the truck when its cool. coolant should pump at idle if theres flow