I recently blew a heater core. It was a waterfall, much more than just a "leak'.

The core changeout was easy yesterday but still no heat. The damper is working fine, checked it right away, the "T" under the hood at the firewall is also OK. I did notice the coolant is hot going into the core but the outlet hose is cold. I'll guess the outlet hose is clogged, possibly where it returns to the block?? Maybe this caused an increase in pressure that finished the old core off??

Yesterday was summer-like, today it's rainy and cold so crawling under the car is not much of an option, so my question is "where does the outlet hose return to the engine? I'm guessing it could be clogged at that point since the hose obviously must slip over a nipple somewhere, which could be a logical spot to check first I suppose. It's hard to follow looking from under the hood.

The car has a little over 50,000 miles on it and is in pristine condition, but it's been driven little in the past 5 years.
Any other ideas?? Thanks....