Does anyone know the exact size or part number of the welch plug behind the water pump housing on a 300TDI please. Think it might be leaking and want to get one in advance before I dig back in again. Yes I did the P gasket with new through bolts (a few weeks ago) but ignored the plug. Still have coolant showing back there, so might be the plug, might be a ****ty job I did of the P gasket fix (even after a block drain with really clean parts and correct torque specs etc) - but would like to be prepared. Thanks, Simon