So, I've been running with a bypassed heater core since I got my truck, which hasn't really been a problem because who uses the heater during summer in Texas?

I got a new heater core and hooked it up (outside of the cab first to make sure it doesn't have a leak) everything looked good, so I ripped off the glovebox, shoved it in it's cubby and delicatly attached the tubes.

I start the truck and a lot of coolant is steadily flowing onto the ground. It wasn't spraying, but it was much more than nothing. Imagine a steady stream of blood coming out of your nose. You know... not a lot at once, but after a while, you'll die of blood loss unless you stop it.

I've got pics to show you as the heating & A/C are not my strong subjects.

Next to my blower, there's a box with heat shields on it with an A/C tube/nipple coming out of it:


And below it all maybe 3/4 of the way to the right there's a tube that looks like it's coming out of the firewall area next to the heater core:


I figured this was a seperate incident from the heater core, because it wasn't leaking at all, nothing in the cab, etc. like the old one. So I bypassed the core again:


And the leak stopped.

Might this be some kind of excess fluid (albeit a metric funk-ton) or perhaps some kind of wicked voodoo magic?

Please help... I'm ever so cold in these dark winter times D:

 

No excess fluid or magic involved that I am aware of. But then the problem always seems easy when you already know the answer. :-)

Suspect either your core has sprung a leak since the checkout you performed, or didn't get the heater hoses on right & tight. Judging by the previous clamp imprints on the hoses, that looks to be good snugness.

Inspect the inlet and outlet tubing for any splits. Perhaps the hoses went on further during the checkout, covering any tubing defect???

Nice job on the heater hoses, hadn't considered the use of the jacketing before.

 

bingo

I guess somehow the fluid was leaking into the cover, but not into the cab and I'm guessing that tube is some sort of drainer. I guess when I tightened the clamps onto the core it felt like a snugger fit than it actually was due to the tight space in there. I need to replace the screw clamp though now cause I tightened it until it started going into loop that stops the screw from turning anymore D:

 

Not sure exactly where that tube is, but I suspect it would be the A/C condensate drain.