OER Parts offers a wide selection of Heater Parts for your 2003 Buick Century. OER Parts offers 2003 Buick Century Expansion Valve, 2003 Buick Century Hose Clamps, 2003 Buick Century Hose Fittings, 2003 Buick Century Hoses and Lines, 2003 Buick Century Vent and Duct Parts.