I would only suggest that since it is a 1998 car with the 3.2 liter V6, he needs to have the rubber portion of the crankshaft pulley checked. There is lots in the archives about these failing.
Benzmac started a thread on this several weeks ago, too.
Crankshaft Balancer Failure! UPDATED
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".