GMPartsGiant.com offers the wholesale prices for genuine 2013 Chevrolet Express 1500 2WD parts. Parts like Heater Assembly are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 4.3L, 8 Cyl 5.3L. Model Code: 1/2 TON CARGO EXPRESS, 1/2 TON PASSENGER EXPRESS.