The original vac pump on my 616 engine went a half million miles with no problems. I heard a noise from the vac pump area one day and posted here. That's when Benzmac told me that the roller could possibly come loose and destroy the motor, so I should remove and investigate. Sure enough the roller was worn out but still intact. I replace the pump.

The good news is that it will give you warning, but you have to listen to the warning and take action. I fully expect that most of the situations where the roller did indeed destroy an engine was because the driver did not heed the warning. When you here noises, investigate before they become bigger problems.

My $0.02,