2000 astro. smelly heat/defrost when on

[USA-1]

Hello
2000 astro. I have noticed for the last month when heat/defrost on a bad smell coming out. Smells like cat pee or amonia smell? Also when shut down vehicle or heat I can hear it like garggle on the passenger side floor. I also do not get heat when selected by dial? it either comes out of vent or defrost location. Any help would be greatly appreciated

[old_master]

The smell/noise is most likely a leaking heater core, there is no fix, replacement only.

Air distribution problem is a cracked, leaking, or broken vacuum hose between the vacuum fitting on the PCV valve, (driver side rocker arm cover) and the vacuum check valve under the hood, (passenger side), near the A/C accumulator.

Hope this helps

[USA-1]

WOW

That sounds expensive? What are we talking $$$ roughly? How long before this becomes a real bad problem? Is it bad to be breathing in that smell?

thanks for your help.