A must to replace when servicing the timing belt. Failure of the water pump on this engine design will result in a broken cam belt causing bent valves and other possible internal engine damage. This water pump features a cast metal impeller. In most cases the stock pump has a plastic impeller which is known to have a high failure rate. The metal impeller water pump is considered an upgrade over the original plastic design. Volkswagen 337/20AE All All Volkswagen Golf IV All 1.8T Volkswagen Golf IV All 2.0 Volkswagen Jetta IV All 1.8T Volkswagen Jetta IV All 2.0 Volkswagen Jetta IV GLI All 1.8T Volkswagen New Beetle All 1.8T Volkswagen New Beetle All 2.0 Volkswagen Passat B5 All 1.8T