One problem related to suspension noise has been reported for the 1998 Cadillac Seville. The most recently reported issues are listed below.
Clunks, squeeks and rubbing noise from rear suspension. Noise apparent when turning up a slope, starting forward from a standing stop, or going over road dips. Reported three times to dealer before they investigated. Last report resulted in dealer fixing what was described as a "missing weld" in the right rear wheel well. However, noise returned shortly after, and now the vehicle is out of warranty. Dealer says they aren't aware of any other rear suspension problems with this make and model. However, another dealer told me Cadillac was aware of rear suspension problems when the car was introduced in January, 1998 (a month before I got mine), and that they were going to be fixed before cars got delivered.