GM Service Manual Online
For 1990-2009 cars only

Cleaning Procedure


    Object Number: 635646  Size: SH
  1. Clean the coolant crossover (3) and water outlet (1) in solvent.
  2. Caution: Refer to Safety Glasses Caution in the Preface section.

  3. Dry the components with compressed air.

Inspection Procedure


    Object Number: 635646  Size: SH
  1. Inspect the coolant crossover (3) for the following:
  2. • Corrosion or damage to the gasket sealing surfaces (4)
    • Corrosion or damage to the bypass hose fitting (5)
    • Corrosion or damage to the threads for the water outlet (2)
  3. Inspect the thermostat housing (1) for corrosion or damage.
  4. Replace the coolant crossover and/or water outlet as necessary.