One problem related to starter solenoid has been reported for the 1998 Buick Lesabre. The most recently reported issues are listed below.
The manifold and gasket had to be replaced. I was told coolant was improperly mixing with my oil causing black smoke to be emitted from my exhaust, the car missing and eventually semi-locking. The locking cause the cone of my starter to crack in two when I attempted to re-start to the tune of a $1,500. Repairfor all. Dealer ackowledged they had this problem with other vehicles. The initial stater replaced was discovered defective and was again replaced on June 25, 2003. A complaint to Buick customer service was fruitless and they were not sensitive at all to the problem encountered.