Thermostat Diagnosis 3.6L (LY7)

Tools Required

J 24731 Tempilstick

The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil-like device which has a wax material containing certain chemicals that 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 outlet coolant pipe.

1. Use a tempilstick in order to find the opening and the closing temperatures of the thermostat.

•	J 24731 188 tempilstick melts at 87°C (188°F). The thermostat should begin to open at 90°C (194°F).

•	J 24731 206 tempilstick melts at 97°C (206°F). The thermostat should be fully open at 107°C (225°F).

2. Replace the thermostat if it does not operate properly between this temperature range.