Worked for Nissan for a bit, watched about half your video. Blue goo is just coolant that's been dripping and ended up solidifying, Nissan coolant is blue. I've actually never seen a failure like you had. Nissan for the most part makes a fairly decent product, as long as it doesn't have a CVT. Parts showing up broken is $#!&ty, and I don't understand why they would make you replace the whole box and not just the heater core? Sent from my SM-N960U using Tapatalk