Pipe assy hardware kit. A combination of parts used to seal the Heater Core Tube. A kit that contains the necessary components for attaching the coolant pipe to it's mounting point. A kit that contains the necessary components for attaching the heater core tube to it's mounting point. Engine Coolant. HVAC Heater Hose Outlet Seal. Included with: Pipe assembly, Pipe assembly and also with heater core, Pipe kit heater core.