AC SYSTEM CODE: 9AQ. Heater core clamp. A combination of parts used to Seal the Heater Core Tube. A part which fits around the Heater Core and tightens, thereby securing the component in place with a Clamping force. Hose Outlet Tube Kit. Retainer. Included with: Heater Core, Heater Core Tube assembly, Pipe Kit, Pipe Kit Heater Core.