2003 Chevrolet Blazer Owner's Manual - Page 384

100,000 Miles (166 000 km) 0 Inspect spark plug wires. An Emission Control 150,000 Miles (240000 km) U Drain, flush and refill cooling system (or every Service. 0 Replace spark plugs. An Emission Control 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. Manual transmission fluid doesn't require change. U Automatic Transfer Case Only: Change transfer case fluid. 12Inspect Positive Crankcase Ventilation (PCV) valve. An Emission Control Service. 60 months since last service, whichever occurs first). See Engine Coolant on page5-23 for what to use. lnspect hoses. Clean radiator, condenser, pressure cap and neck. Pressure test the cooling system and pressure cap. An Emission Control Service. 0 Inspect engine accessory drive belt. An Emission Control Service. 6-25