GM Service Manual Online
For 1990-2009 cars only
  1. Clean the engine coolant sealing surfaces.

  2. Object Number: 2028006  Size: SH
  3. Install the engine coolant thermostat (1).
  4. Install the engine coolant seal (2).
  5. Install the engine coolant thermostat socket (3).
  6. Caution: Refer to Fastener Caution in the Preface section.

  7. Install the 4 engine coolant thermostat bolts (4) and tighten to  8 N·m (71 lb in).