For 1990-2009 cars

### Draining Procedure

Caution: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -- possibly with explosive force -- spewing the solution over the engine, fenders and the person removing the cap.

Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

Notice: The 4.0L engine uses DEX-COOL™ and GM coolant supplement (sealant) P/N 3634621 specifically designed for use in aluminum engines. Failure to use the engine coolant supplement (sealant) and the approved coolant antifreeze could result in major engine damage. When refilling the cooling system, add three pellets of the engine coolant supplement sealant GM P/N 3634621 to lower the radiator hose.

1. Open the radiator drain cock at the bottom of the radiator.
2. Remove the plugs in the engine block.
3. Completely drain the system.
4. If the coolant is dirty, or if there are deposits in the radiator, flush the cooling system before refilling. Refer to Flushing .
5. Remove the cooling system pressure cap.

5.1. | Clean, test, and replace the cap if needed.

5.2. | Clean the radiator/cooling system filler neck. Inspect the filler neck.

6. Disconnect the hoses from the coolant reservoir surge tank. Remove the reservoir or surge tank.
7. Pour out any fluid.
8. Clean the inside of the reservoir using soap and water.
9. Thoroughly flush the reservoir with clean water. Then drain the reservoir or surge tank.
10. Install the reservoir or surge tank. Connect the hose(s).

### Filling Procedure

1. Close the radiator drain cock.
2. Install the block drain plugs if removed.

Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

Notice: Pure coolant can be added to raise the boiling point of the coolant, but too much will affect the freezing point. Do not use a solution stronger than 70 percent, as the freeze level rises rapidly after this point. Pure coolant will freeze at -22°C (-8°F).

3. Refill the cooling system. In order to ensure sufficient engine cooling, freezing and corrosion protection, maintain the coolant protection level at -37°C (-34°F) or lower.
4. Set the heater/A/C control in any A/C mode except MAX. Set the temperature to the highest setting.
5. Allow the engine to continue idling until the lower radiator to coolant pump hose becomes hot.
6. Cycle the engine speed up to about 3,000 RPM and back to idle 5 times. On the L36 and L67 engines, slowly open the bleed valve on the rear of the thermostat housing for about 15 seconds in order to release any trapped air in the cooling system.
7. After the air has been released, fill the radiator. Install the radiator pressure cap/surge tank. The arrows on the radiator pressure cap must line up with the coolant recovery tube.
8. Allow the engine to cool to the outside temperature. Check the coolant level. If the coolant level is not at the Add (of Full Cold) mark, add coolant until the coolant reaches the mark.