Draining Procedure

Fig 1: Identifying Radiator Drain

Courtesy of GENERAL MOTORS CORP.

1. Place a drain pan under the radiator drain cock.
2. Place the end of the tube in the drain pan.
3. After the engine cools down, remove the radiator cap.
4. Turn the drain cock counterclockwise in order to allow the coolant to drain.
5. Allow the coolant to drain from the system until the flow stops.
6. Place a drain pan under the engine block drain hole plug.
7. Remove the drain hole plug from the engine block.
8. If equipped with the 4.3L, remove the drain hole plug from the engine block.
   Fig 2: Removing Drain Hole Plug From Engine Block (4.3L)

   Courtesy of GENERAL MOTORS CORP.
9. If equipped with the 5.0L and 5.3L, remove the drain hole plug from the engine block.
   Fig 3: Removing Drain Hole Plug From Engine Block (5.0L & 5.3L)

   Courtesy of GENERAL MOTORS CORP.
10. If equipped with the 6.5L, remove the drain hole plug from the engine block.
    Fig 4: Removing Drain Hole Plug From Engine Block (6.5L)

    Courtesy of GENERAL MOTORS CORP.
11. If equipped with the 8.1L, remove the drain hole plug from the engine block.
12. Allow the coolant to drain from the block until the flow stops. There may be more drainage from the radiator at this time.
13. Apply Teflon Pipe Sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the engine block coolant drain hole plugs.
    CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
14. Install the engine block coolant drain hole plugs.

Tighten 

• Tighten the 4.3L, 5.0L, 5.7L and 8.1L engine block drain hole plugs to 20 N.m (15 ft lbs).
• Tighten the 6.5L engine block drain hole plugs to 25 N.m (18 ft lbs).
• Close the radiator drain cock.
  Fig 5: Removing Drain Hole Plug From Engine Block (8.1L)

  Courtesy of GENERAL MOTORS CORP.