300E 4MATIC (124.230) L6-3.0L (103.985) (1990)
Removing The Heater-A/C Box Cover
2. Screw out the 4 screws (17) and remove the cover (19).
Removing The Heater Core
3. Unclip the hose clamps (22 and 23) on the heater hoses.
4. Push off the connecting rod for the fresh air/recirculated air flap (arrow).
5. Remove the three screws (20) and remove the vacuum actuator (42).
6. Pull the heater core (9) upward and out.
Removing The Left And Right Mounting Screws
7. Remove the two screws (arrow) on the left and right sides.