1998 is the first year of the V6 in the E320, and they had trouble with harmonic balancers. Inspect it. If it hasn't been replaced, do it now.

There is a loooooooong thread on harmonic balancers.

Here it is:

http://www.peachparts.com/shopforum/showthread.php?threadid=63512

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".