Extended Mileage Maintenance
EXTENDED MILEAGE MAINTENANCEService the cooling system as follows:
^ Drain, flush and refill the cooling system every 240 000 km (150,000 miles) or every 60 months, whichever occurs first.
^ Inspect the hoses.
^ Clean the radiator, condenser, pressure cap and the neck.
^ Pressure test the cooling system.
Coolant Type
A 50/50 mixture of clean water (preferably distilled) and use only GM Goodwrench(R) DEX-COOL(R) or Havoline(R) DEX-COOL(R) (orange-colored, silicate-free) coolant, conforming to GM Specification 6277M.
CAUTION: If silicate coolant is added to the cooling system, premature engine, heater core or radiator corrosion may result. In addition, the coolant will require change SOONER, at 50 000 km (30,000 miles) or 24 months.
This is an emission control service, refer to Service and Repair / Service Definitions / Emission Control Service.