The intake gasket and main engine gasket needs replacing too early.
For an older car it still runs well. However it has some issues. Windshield wiper motor does not park the wipers in resting spot. Drivers window does not work anymore. It is getting a little rust on bottom edges of body. Has a calanoid issue that acts up a little and affects shifting on occasion. The main gasket had to be replaced also the intake gasket because on Buick centuries they do not last long and some say it should have been fixed by the makers of this car.