Thermostat Inspection

Reference: THERMOSTAT REMOVAL AND INSTALLATION 

• Make sure that air bleed valve (1) of thermostat is clean.

  Should this valve be clogged, engine would tend to overheat.

• Check to make sure that valve seat is free from foreign matters which would prevent valve from seating tight.
• Check thermostat seal (2) for breakage, deterioration or any other damage.
  Fig 1: Checking Thermostat Seal

  Courtesy of SUZUKI OF AMERICA CORP.
• Check thermostatic movement of wax pellet as follows:
  • Immerse thermostat (1) in water, and heat water gradually.
  • Check that valve starts to open at specific temperature.

    Temperature at which valve begins to open 

    80 - 84°C (176 - 183°F) 

    Temperature at which valve become fully open 

    95 - 97°C (203°F) 

    Valve lift 

    More than 8 mm at 95°C (203°F) 

If valve starts to open at a temperature substantially below or above specific temperature, thermostat unit should be replaced with a new one. Such a unit, if reused, will bring about overcooling or overheating tendency.

Fig 2: Checking Thermostat Opening Temperature

Courtesy of SUZUKI OF AMERICA CORP.