Use one of the following procedures in testing for a malfunctioning thermostat.
J 24731 Tempilstick
The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil like device. It has a wax material containing certain chemicals which melt at a given temperature. Temperature sticks can be used to determine a thermostat's operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing.
• | J 24731-188 tempilstick melts at 87°C (188°F). The thermostat should begin to open. |
• | J 24731-206 tempilstick melts at 97°C (206°F). The thermostat should be fully open. |
Inspect the operation of the thermostat by hanging the thermostat on a hook in a 33 percent glycol solution.
In order to inspect if the thermostat valve is opening properly, perform the following test:
In order to inspect if the thermostat valve is closing properly, perform the following test: