Before servicing the vehicle, refer to the Precautions Section.
NOTEDisconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.
NOTEIf working near and/or around the SRS system and components, be sure to properly disable the SRS system. See disarming/arming the SRS system.
NOTEFor vehicles equipped with OnStar (RPO UE1), with battery backup, the backup battery is a redundant power supply to allow limited ONStar functionality in the event of a main battery power disruption to the OnStar module (VCIM). Do not disconnect the main vehicle battery or remove the OnStar fuse with the ignition key in any position other than OFF. Retained accessory power should be allowed to time out or be disabled by opening the driver-s side door before disconnecting power. Disconnecting power to the module in any way while the ignition is ON or with the retained accessory power activated may cause activation of the OnStar backup battery system and will discharge and permanently damage the backup battery. Once the backup battery is activated it will stay on until it has completely discharged. The backup battery is not rechargeable and once it is activated, it must be replaced.
- Park the vehicle on a level surface.
- Disconnect the negative battery cable.
- Remove the coolant reservoir filler cap. Be sure the engine is cool before removing this cap.
Open the radiator drain plug and drain the coolant into an acceptable container. Be sure to properly dispose of used coolant.
- Open the heater air bleed valve (1), just above the water pump, on the water pump inlet. Position a shop towel underneath the bleed valve to prevent coolant from splashing on the distributor.
Remove both knock sensors.
- Allow the cooling system to drain completely.
- Installation is the reverse of the removal procedure.
- Close the radiator drain plug.
- Install the knock sensors.
Tighten the knock sensors to 14 ft. lbs.
NOTEPure 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.
- Fill the system to the FULL COLD mark, thru the coolant recovery reservoir.
- When bubbles disappear and only the coolant is visible, close the heater air bleed valve.
- Connect the negative battery cable.
- Block the wheels. Position the selector lever in PARK or NEUTRAL. Set the parking brake.
- Run the engine with the recovery reservoir filler cap off, until the thermostat opens.
- Open the heater air bleed valve.
When the bubbles disappear and only the coolant is visible, close the heater air bleed valve. Place a shop towel underneath the bleed valve in order to prevent coolant from splashing on the distributor.
NOTEWhen filling the cooling system add two engine coolant supplement sealer pellets (part number 3634621) or equivalent.
- Fill the cooling system thru the coolant recovery reservoir, until the coolant level is about 1 inch above the FULL COLD mark.
Install the coolant recovery reservoir filler cap.
NOTEThe low coolant warning/indicator light may come on. If after operating the vehicle so that the engine heats up and cools down three times, the low coolant warning/indicator light does not go out, or fails to come on at the ignition check, and the temperature warning/indicator light comes on, immediate action is required. Turn OFF the engine and allow the vehicle to cool. Do not remove the coolant recovery reservoir filler cap at this time.
- After the engine reaches normal operating temperature check the system for coolant leaks. Correct as required.
- Test the coolant for proper mixture concentration using tools J23688 and J26568.
- Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.