1997 Buick Riviera Owner's Manual - Page 335

I Short TriplCity Maintenance Schec 78,000 Miles (130 000 kna) 0Change engine oil and filter (or every 3 months, whichever occurs first). An Emission Control Service. 81,000 Miles (135 000 km) 0Change engine oiland filter (or every 3 months, whichever occurs first). An Emission Control Service. 0Lubricate chassis components (or every 6 months, whichever occurs first). (See footnote#.) Rotate tires. See "Tire Inspection and tion Rotation'' inthe Index for proper rota pattern and additional information. (See footnote +.) DATE MILEAGE ACTUAL SERVICED BY: 7-22