I've recently noticed a puddle of fluid under my PS. It's dripping down the header. Looking up from under, it appears it's coming from my heater core box. There's a weep hole in the bottom that I assume is for condensation, and it looks like coolant (green).
For those who have dealt w/ heater core leaks, is there a consistent place it's leaking from? I'm hoping it's just an external, soft part (hose) and not a corroded core which would require removal and replacement.

 

You need a hew heater core from what you are describing.

Rock Auto has them starting at $23 +shipping, so maybe $30 total and if your truck does not have AC its not a bad job to do.

 

I have factory AC. What does this job look like? It appears I need to unbolt 3 bolts from the cab side. Do I need behind the dash? I'm guessing I'll need to disconnect the heater valve wire from the temp selection switch.

 

Be thankful it's leaking outside, and not down the firewall inside onto the carpet... had to do a few, I'd rather do two on my 63, 66, 77 or other 77 than on my 02 F350 again...

 

Buy the new core from a radiator shop and have them pressure check it for you. May cost more but it's worth it in the long run.

 

"PS" means passenger side I'm guessing.

Over the last year or so chasing what presented itself as a heater core leak, started a few days after I had changed hoses, and the replacement hose was a loose fit but I used screw clamps, thinking would be fine. We were on a drive one damp day, turned defrost on, windows fogged up and stunk. Pulled over, wiped all dry, shut defrost off, shut the two ball valves I had in the hoses. If I write it all again, gonna be a really long post here, but eventually found out my 1973 era heater core was fine, issue was hoses leaking at the connection because dummy used 3/4 hose and screw clamps, let coolant go into housing. Now, after finally getting the mess cleaned up, new 5/8 hoses, springy constant pressure clamps, I can use defrost and heat again. I was able to fully test my heater core with both 20 inches vacuum and air @ 15 psi because I had those two ball type valves in line.

Reading this thread, I might reopen that evap drain as it would let my heater core drain outside if it ever does leak. I don't have a working AC any longer, and thought might be pulling in moisture laden exterior air on a misty day, so I plugged it, might rethink that decision. I can get a new duckbill nipple end.


Couple threads might help, pretty sure some pics there that might help you.
Changing another heater core... - Ford Truck Enthusiasts Forums
and
Maybe I solved the "Misting Glass Mystery" ? - Ford Truck Enthusiasts Forums

 

thanks for the info.
yes, PS refers to passenger's side.
As I'm writing this, I just remembered that I never hooked up hte vacuum line when I reassembled everything. (recently took apart the dash, removing the hvac controls/radio for painting the dash) I did notice a loud noise when I started the truck from behind the dash. I assume this would not be related in any way w/ the leak, but at least would explain the sound.

 

I generally leave the system off when parked and don't hear noises behind the dash at startup, but if left on then I can understand such noises as vacuum builds and starts pulling vacuum motors adjusting the doors according to setting. I don't hear the noises unless I change settings if is any vacuum in the vacuum reservoir.

 

Youi are correct, those old ones come out from the inside after you take the heater box apart
Work from behind the glove box
You can do it
There is nothing else inside that case, your core leaks and it needs to be replaced