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. If the coolant is dirty, or if there are deposits in the radiator, flush the cooling system before refilling. Refer to Flushing .
3. Remove the radiator/surge tank pressure cap. Refer to Radiator Assembly .

3.1.	Clean, test, and replace the cap if needed. Refer to Radiator Diagnosis .

3.2.	Clean the radiator/cooling system filler neck. Inspect the filler neck.

4. Disconnect the hoses from the recovery reservoir/surge tank. Remove the reservoir/surge tank.

•	On the L36 & L67 engines, refer to Coolant Recovery Reservoir Replacement .

•	On the L47 engine, refer to Radiator Surge Tank .

5. Clean the coolant recovery reservoir/surge tank.

•	Pour out any fluid.

•	Clean the inside of the reservoir/surge tank using soap and water.

•	Thoroughly flush the reservoir/surge tank with clean water. Then drain the reservoir/surge tank.

6. Install the reservoir/surge tank. Connect the hose(s).

•	On the L36 & L67 engines, refer to Coolant Recovery Reservoir Replacement .

•	On the L47 engine, refer to Radiator Surge Tank .

Tools Required

GM approved Recycling System such as Pro Clean (Available in the GM Dealer Equipment Program)

Whenever the cooling system needs maintenance or repairs, remove and replace the coolant with qualified new or recycled coolant.

If you only drain the radiator, up to 50 percent of the used, contaminated coolant can remain in the cooling system.

Use any of the following methods in order to remove the coolant:

1. Close the radiator drain cock.

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).

2. 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.
3. Set the heater/A/C control in any A/C mode except MAX. Set the temperature to the highest setting.
4. Allow the engine to continue idling until the radiator outlet hose becomes hot.



5. 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.



6. After the air has been released, fill the radiator. Install the radiator/surge tank pressure cap. The arrows (1) on the pressure cap must line up with the overflow tube (2). (L36 and L67)
7. Allow the engine to cool to the outside temperature. Then, check the coolant level in the reservoir/surge tank. If the coolant level is not at the appropriate mark, add coolant until the coolant reaches the proper level.