Sierra Classic 1500 4WD V6-4.3L (2007)
4. Connect the heater hose to the heater core.
Firmly push the quick connect onto the heater core pipe until you hear an audible click.
5. Install the air intake tube.
6. Fill the cooling system. Refer to Draining and Filling Cooling System (Static Fill) Draining and Filling Cooling System (w/RPO HP2) Draining
and Filling Cooling System (Vac-N-Fill).