[boschmann]

First thing get a good manual, I like Bentley's. You do not have to discharge the A/C to get the heater core out. There are six clips that hold the two housings (A/C & heater) together. Remove them & the two 10mm nuts for the heater box at the firewall inside the engie compartment. You may also (recommended) have to loosen the dash to raise it up enough to get the box out. The back two & top clips are a pain & you won't get them all back on. The job is really difficult the first time you do it. It is very difficult to get the two box halves aligned when putting them back together, you may have to loosen the nuts for the A/C section.