Correction 2

Replace Heater Inlet and Outlet Pipe Adapters and for Park Avenue/Ultra ONLY - Replace the Heater Inlet Hose Assembly





For the vehicles, see table.

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 heater inlet and/or outlet pipe adapters and/or hoses while the engine is hot and cooling system 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 adapters and/or hoses. Under certain conditions, the ethylene glycol in the engine coolant could be ignited.

Caution:
An electric fan under the hood can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.

Repair Procedure Tools Required

^ J 38185, Spring Hose Clamp Pliers

^ J 37097-A, Hose Clamp Remover/Installer

Parts Required

^ P/N 12569584 - Heater Inlet Pipe Adapter Assembly

^ P/N 12569648 - Heater Outlet Pipe Adapter Assembly

^ P/N 25699450 - Heater Inlet Hose Assembly (For 1999 Park Avenue/Ultra ONLY)

1. Drain the cooling system.

Refer to the Draining and Filling Cooling System procedures in the Engine Cooling sub-section of the Service Manual.





2. Remove the heater inlet and outlet pipe adapter bolts (2 and 5) from the heater inlet and outlet pipe adapters (3 and 4).

3. Remove the heater inlet and outlet pipe adapters (3 and 4) from the engine.

4. Mark the position of the heater pipe adapter bracket on the heater hose.

Remove the heater inlet and outlet pipe adapters (3 and 4) from the heater hoses (1 and 6) using the J 38185, Spring Hose Clamp Pliers.





5. On 1999 Park Avenue/Ultra ONLY:

5.1. Remove the hose clamp from the heater inlet hose at the heater core using the J 37097-A, Hose Clamp Remover/Installer.

5.2. Remove the heater inlet hose assembly.

5.3. Remove the hose clamps from the hose assembly.

6. On 1999 Park Avenue/Ultra ONLY:

6.1. Transfer the adapter bracket mark from the old hose to the new heater inlet hose assembly, P/N 25699450.

6.2. Install the hose clamps to the new hose assembly.

6.3. Install the new hose assembly to the heater core.

6.4. Install the hose clamp to the heater inlet hose at the heater core using the J 37097-A, Hose Clamp Remover/Installer.





7. Align the bracket of the new heater pipe adapter with the mark on the heater hose.

7.1. Install the new heater inlet pipe adapter (3), P/N 12569584, and the new heater outlet pipe adapter (4), P/N 12569648, to the heater hoses.

Align the new heater pipe adapter bracket with the mark on the heater hose.

7.2. Reposition the heater hose clamps using the J 38185, Spring Hose Clamp Pliers.

8. Apply a thin layer of lubricant, such GM Goodwrench(R) Rubber Lubricant, P/N 12345884 (in Canada, use P/N 5728223), or equivalent to the O-rings of the heater inlet and outlet pipe adapters.

9. Install the heater inlet and outlet pipe adapters (3 and 4) to the engine.

Ensure the pipe adapters are properly seated.

10. Install the two heater inlet and outlet pipe adapter bolts (2 and 5).

Important:
Do not exceed the specified torque. The isolation bolts are intended to eliminate the hard interface between the generator mounting bracket and the heater inlet and outlet pipe adapters. After tightening the bolts, ensure the hose has movement.

Tighten

Tighten the two heater inlet and outlet pipe adapter bolts to 10 N~m (89 lb in).

11. Fill the cooling system.

Refer to the Draining and Filling Cooling System procedures in the Engine Cooling sub-section of the Service Manual.