My water pump has failed and I'm considering replacing it myself but I'm
unsure whether it needs a special coolant bleeding process afterwards to
make sure there are no airlocks. I heard for some cars (Ford Sierras) this
is essential to avoid overheating hassles but is this necc for a MB? The
'special process' I believe amounts to briefly undoing various bleed valves
round the engine and heater to clear air pockets.