Thermostat Inspection - L61

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use extreme care and do not damage or scratch the machined aluminum surfaces. Coolant leaks will result.

Fig 1: Removing Thermostat From The Housing

Courtesy of GENERAL MOTORS CORP.

In order to verify the thermostat valve is opening properly, remove thermostat from the housing and perform the following test:

Using wire hook, completely submerge the thermostat in glycol solution. The solution should be 11°C (22°F) ABOVE the temperature indicated on the thermostat.
Thoroughly agitate the solution. Under these conditions, the thermostat should open.

Fig 2: Submerging The Thermostat In Glycol Solution
Courtesy of GENERAL MOTORS CORP.

In order to check if the thermostat is closing properly, perform the following test:

Completely submerge the thermostat in the glycol solution. The solution should be 6°C (10°F) BELOW temperature indicated on the thermostat valve.
Thoroughly agitate the solution. Under these conditions, the thermostat valve should close completely.

Fig 3: Submerging The Thermostat In Glycol Solution
Courtesy of GENERAL MOTORS CORP.