1998 Chevrolet Express Van Owner's Manual - Page 348

Long Tripmighway Maintenance Schedule -- Gasoline Engines I 0 Change automatic transmission fluid and filter if the vehicle's GVWR is over 8600 lbs. or if the vehicle is mainly driven underone or more of these conditions: - In heavy city traffic where the outside temperature regularly reaches 90 O F (32°C) or higher. - In hilly or mountainous terrain. - When doing frequent trailer towing. - Uses such as found in taxi, police or delivery service. 0 If you haven't used yourvehicle under severe service conditions listed previously and, therefore, haven't changed yourautomatic transmission fluid, change both the fluid and filter. 0 Inspect Positive Crankcase Ventilation (PCV) valve. An Emission Control Service. 150,000 Miles (240 000 km) 0 Drain, flush and refill cooling system (or every 60 months since last service, whichever occurs first). See "Engine Coolant" in the Index for what to use. Inspect hoses. Clean radiator, condenser, pressure cap and neck. Pressure test the cooling system and pressure cap. An Emission Control Service. DATE I ACTUAL MILEAGE I SERVICEDBY: I [