Heater core hose routing

[wazzabie]

What is the proper way to route the heater core hoses? Both of these are from low millage vehicles.

[smupser]

The pic to the right is correct, you can see in the pic on the left there’s a provision for a heater hose bracket which in the pic is being used by a zip tie for something else. Plus, you want it away from hot exhaust

[wazzabie]

Here is another photo I found of a 77 with 14k miles.

[Dead Parrot]

Possible both pics in post 1 are correct as one is with AC and the other without. Note that in the AC pic(black firewall), the heater core inlets are farther to the passenger side then the heater only heater core inlets(orange firewall).

[Just call me Sean]

There are several ways to do it and still be correct.

[geezer#99]

The only concern when hooking up hoses is where they connect.
Feed line to heater core comes from intake to bottom connection on core, top of core back to
Water pump or to the rad. A/c trucks usually had return to rad.
Length of hoses can be as short as possible or looped onto fender well.
Also hose sizes are 5/8 for bottom core hook up, 3/4 for top core return line.

[kwmech]

Looped to the inner fender is preferred as you do not want the weight of the hoses hanging off the heater core hose ends

[400/400]

As far as returning to water pump or radiator, I’ve noticed automatic trucks return to the rad. Presumably to help warm the transmission in cold weather. (The return is right above the transmission heat exchanger in the radiator.)

All manual transmission trucks I’ve seen return to the water pump.

[MJN]

The service manual shows the heater hose routings pretty clearly- it depends on if the truck is auto or manual trans as well. Auto trans equipped trucks use the radiator and manual trans trucks use the water pump.

[wazzabie]

Interesting that for the 350 v8 model the routing is shown behind the header pipe. It seams like it would touch the header pipe. If the header pipe is hot enought perhaps it would damage the hose.