Honda Civic Service Manual page 1417

Overhaul
'1. Remove the two self-tapping screws and the heater
core cover.
2.
Pull out the grommet from the heater core pipes.
3.
Remove the self-tapping screw and the clamp.
GROMMET
Pull out the heater core from the heater unit.
NOTE: Be careful not to bend the inlet and outlet
pipes during heater core removal.
Assemble in the reverse order of disassembly.
HEATER CORE COVER
21-41