heater core position

[69gmc292]

i changed out the heater core on my 69 gmc C1500 and was wandering which way the heater inlets went my truck never came with a core and i think the 3/4 inlet is on the top thank you

[john]

I think you are right.

[72ChevyAZ]

How was that whole job (installing a heater core)? I just found out today that mine is leaking. Never tackled this but gonna give it a try. Anyways, here's a bump for ya.

[69TowRig]

Originally Posted by 72ChevyAZ

How was that whole job (installing a heater core)? I just found out today that mine is leaking. Never tackled this but gonna give it a try. Anyways, here's a bump for ya.

It is not bad, hang the hood from something above (or take the hood off), remove the passenger side hood hinge. Disconnect and remove the fan, then all the screws, carefully pull the box away from the firewall and disconnect the heater flap from the control cable. I did that over a year ago, I think you might have to undo something inside the cab too. It is pretty obvious when you are in the midst of it.

Originally Posted by john

I think you are right.

I'm in agreement (3/4" on top).

[70GMCer]

Just did mine back in Oct. I didn't have to remove the hood hinge though. Just drop the inner fender down.

[68C15]

in the 5/8 and out the 3/4. otherwise you will create higher pressure in the core leading to eventual blow-out. that is the way the engineers made them.

if you see a car with the same size on both then the feed has a restrictor inside.