GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 1801280  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling.
  2. Remove the bypass valve snap ring.
  3. Remove heater water bypass valve.
  4. Inspect the bypass valve O-ring seal for damage, replace as required.

Installation Procedure


    Object Number: 1801280  Size: SH
  1. Lbricate the bypass valve O-ring seal with clean engine coolant.
  2. Install heater water bypass valve.
  3. Install the bypass valve snap ring.
  4. Fill the cooling system. Refer to Cooling System Draining and Filling.