Quick-Lok™ 5/8″ HVAC Heater Hose Connectors (28500) by Gates®. Location: Heater to Pipe-1. Quantity: 1 Piece. Superior aluminum cooling system connectors which carry coolant from the tensioner to the engine. Precision sized ends, with high quality EPDM O-rings, to create a perfect seal. Developed to replace the failure prone plastic connectors which become brittle and crack from the high heat of the engine. Manufactured by the OEM tensioner supplier.