1997 GMC Suburban Owner's Manual - Page 385

I Short TripKity Maintenance Schedule -- Gasoline Engines In hilly or mountainous terrain. - When doing frequent trailer towing. - Uses such as found in taxi, police or delivery service. - I 150,000 Miles (240 000 km) 0Drain, 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 cooling system and pressure cap. An Emission Control Service. If you do not use your vehicle under any ofthese conditions, the.fluid andfilter do require changing. not El Inspect Positive Crankcase Ventilation (Pcv)valve. An Emission Control Service. DATE ACTUAL MILEAGE SERVICED B Y DATE ACTUAL MILEAGE SERVICED B Y 7-29