A leaking water pump, moisture at the pump shaft or an engine that creeps up in temperature are classic symptoms of a 122 with many miles on its cooling system. This category gathers parts for the pump and thermostat job on the B18 (from the 1962 model year) and B20 (from Aug 1968), so the correct version is matched to the engine.
The group includes water pumps, thermostat and thermostat housing, plus gaskets, seal rings, gasket sets and a mounting kit with screws needed for the replacement. During a rebuild, the pump shaft play and the gasket surfaces against the block are typical check points – a worn pump often gives squeaking, leakage and, in the worst case, overheating. The thermostat controls the operating temperature; one stuck open gives slow warm-up, one stuck closed gives rapid overheating. Always replace gaskets and seal rings in the same go for a tight result.
