All I can say is I would interpret "cost reasons" as the early ones self destruct and costs them (MBNA) a new engine (under warranty) and of course the factory warranty has long since run out on a 20 year old car.
Take my word for it, you are on borrowed time with an early style Vac Pump!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!