I have spent some interesting hours this weekend changing the heater core. This is a job everyone should try. I think BMW, when building the car started the heater core and built the rest of the car around it. Luckily the a/c charge was blown so I didn't have to deal with that. I also changed the condensor, condensor fan, and repaired the evaporator fan. It should be blowing cold by Wednesday. I also have a new chip coming Wednesday for the Motronic. I can't wait. Bob 77' with 85' 3.5