2000 chevy blazer LT 4x4 4.3l heater core replacement
 

well I dug into it pretty fast after getting the dash out I can see the top of the core in the black enclosure but is mine different since mine is a loaded version, a/c, etc. the top does not appear to be coming off.is it suppose to or with mine the bottom needs to come off also ? I started removing bolts on the fire wall and all . I cut the service thing open and got the 10mm bolt on the top out . i was trying to split the black cover in the engine bay apart but haven't yet. it looks two bolts on the bottom passenger side. are left but have to be wrenched out from the firewall side and I cant find them. have I gone to far and just need to rip the top off?????? there is a 1" white plastic flapper door arm piece sticking up which would make the black plastic have to go up first . 8pm- to 1am of time invested so far. hope I get some good answers thanks .....