Rich - a fellow I know recently bought a very nice 300CD in Colorado and felt confident to drive the car back to Southern California. Somewhere in Arizona the vacuum pump exploded taking with it the timing chain, breaking the cam in half and destroying several of the cam towers. He had the car flat bedded to Monterey Park where I saw the engine. He was able to get a good engine from a wreck but I cannot imagine the total cost for all of this. I now always replace the vacuum pump as a maintenance item every 130,000 miles and always use a new pump as opposed to rebuilding the vacuum pump. Cheap insurance.