Cooling System Bleed

1. Refill the cooling system with a coolant meeting GM Specification 1825-M. To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37°C (34°F) or lower. Use a solution that is no more than 70 percent antifreeze.

CAUTION: Under some conditions, the ethylene glycol engine coolant is combustible. To help avoid being burned, DO NOT spill antifreeze or coolant on the exhaust system or hot engine parts.

2. Place the Heater / AC control in any AC mode except 'MAX" and the temperature to the highest setting.

3. Allow the engine to continue idling until the lower radiator to coolant pump hose is hot.

Thermostat And Housing:

4. Cycle the engine speed up to about 3000 rpm and back to idle five times. Slowly open bleed valve on the rear of the thermostat housing for approximately 15 seconds to expel any trapped air in the cooling system.

5. After the air has been expelled, fill the radiator. Install the radiator pressure cap, making sure the arrows on the cap line up with the coolant recovery tube.

6. Allow engine to cool to outside temperature, then check the coolant level in the reservoir. If not at the "ADD" (of "FULL COLD") mark, add coolant until it is.