41mm Water Pump Wrench - 1/2in.Dr For use on older GM - Vauxhall / Opel engines where the water pump is used to adjust the camshaft belt tension. Also used on Chevrolet / Daewoo vehicles. Engines : 1.2 / 1.3 / 1.4 / 1.6V / 1.6D / 1.8 OEM Codes : KM421A | J-42492