Where in the TSRM is the heater core???
What position does it sit in the case???
Tube inlet/outlet positions ???
I found this blowup in the TSRM parts catalog.
Which seems to show that air actually should NOT easily get trapped in the core.
Here is one from CSK (Checkers-Schucks-Kragen) parts stores.
Ready-Aire #398296 List is $96
Same part # here on Amazon for $53.
http://www.amazon.com/GDI-Proliance-.../dp/B000C89OMA
Same # here for $46.
http://www.partsamerica.com/ProductL...or=Heater+Core
Most online stores want $216. Crazy!