Heater Core
You need to remove the dash part that holds the glove box. The right side consol cover. The center cluster has to come out (don't miss the two screws that hold it to the consol plate)to get at the ducts. Once this is all out of the way you can see the box that contains the core.
Disconnect everything that attaches to the box (vac line, heater control etc).
There are either 2 screws or 3 screws visible from the inside that need to be undone. There is one screw on the upper passengerside firewall that you need to get at from the engine compartment. Most forget this one and break their box. I know the core box attaches to the box that contains the blower but can't remember if it was attached with screws. If this is the case you will see these. Its the one on on the firewall most miss.
Drain the coolant. Crawl under the car and detach the two hoses that go to the core. Some are on so tight they will not detach. If this is the case cut the hoses as close to the core connection as possible. Then cut the remaining rubber off the core...the core box will not come out with the rubber there, the holes in the firewall are too small.
Go back inside. It takes a GENTLE pulling,lifting and twisting motion to get the core box out. It does come out....a bit tight.
Open the box up and replace the core. Lube everything up. check for debri in the blower area...clean it out if you find any.
Install in the reverse. Should take 2 to 6 hours.
Jim
Here's a write up with pics that might help...click here...









