All Cadillac models offered the year previous were carried over to 1998.
| The 1998 Cadillac had a 17-symbol vehicle identification number (VIN) stamped on a metal tag attached to the upper left surface of the cowl visible through the windshield. The code was as follows: | ||
| POSITION | DIGIT | MEANING |
| 1 | 1 or 4 | manufacturing country (United States) |
| 2 | G | General Motors |
| 3 | 6 | Cadillac |
| 4 & 5 | car line series |
|
| 6 | the body style: |
|
| 7 | the restraint code |
|
| 8 | the engine |
|
| 9 | check digit | - |
| 10 | model year | W = 1998 |
| 11 | the assembly plant | - |
| 12-17 | the production sequence number | - |