1998 Oldsmobile 88 Owner's Manual - Page 318

I Long TripmighwayMaintenanceSchedule I 0 Change automatic transaxle fluid and filter if the vehicle is mainly driven under one or moreof these conditions: 90°F In heavy city traffic where outside temperature regularly reaches the (32O C) or higher. In hilly or mountainous terrain. When doing frequent trailer towing. Uses such asfound in taxi, policeor delivery service. If you do not use your vehicle under any of these conditions, the fluid and filter do not require changing. 150,000 Miles (240 000 km) 0 Drain, flush and refill cooling system (or every months since last service, 60 whichever occurs first). See "Engine Coolant"in the Index for what to use. Inspect hoses. Clean radiator, condenser, pressure and neck. Pressure test cap the cooling system and pressure cap. An Emission Control Service. DATE 7-29