1998 GMC Suburban Owner's Manual - Page 401

1 Long Tripmighway Maintenance Schedule -- Gasoline Engines 1 100,000 Miles ( I 66 000 km) 17 Inspect spark plug wires. An Emission CoI~tl-ol Service. 0 Replace spark plugs. Arz Emission Corztrol Service. 0 Change automatic transmissionfluid and filter if the vehicle is mainly driven under one ormore of these conditions: - In heavy city traffic where the outside temperature regularly reaches 90°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 your vehicle under severe service conditions listed previously and, therefore, haven't changed your automatic transmission fluid, change both the fluid and filter. 0 Inspect Positive Crankcase Ventilation (PCV) valve. An Emis.s'iou Corltrvl Serr*icc?. DATE ACTUAL MILEAGE I 1 SERVICEDBY I 150,000 Miles (240 000 km) 0 Drain, flush and refill cooling system (or every 60 months since last service, whichever OCCUI-sfirst).See"EngineCoolant" 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 Ser-vice. MILEAGE 7-37