Hey guys! Hope all is well with everyone. My name is Patrick and I've been dealing with a very high pitched and loud whistle coming from the right side of the engine bay on my 2012 MDX. I used a funnel and tube technique to find that it's coming from the bottom of this "nipple" (I don't know exactly what to call it) that's on the water passage right where the thermostat housing is.

I'm looking for a solution to fix that other than replacing the entire water passage. I was thinking about trying some JB Weld on it but I wanted to come here and pick your brains before attempting that as I don't know exactly what it is. What's the purpose of that piece? Is coolant traveling through there? Is air traveling through there? I'm confused because it's attached to the water passage system where coolant travels but on the other end it's connected to the pcv breather system. There's no coolant leaking from it. I thought maybe a vacuum leak?

This problem started after removing the air intake system and front valve cover to replace damaged tube seals. I'm thinking maybe when I removed the breather tube from the intake hose it may have pulled on this piece as well and caused some damage.

Any help will be greatly appreciated.