Thermostat Diagnosis LA3, LY9
Thermostat Test Procedure Using Tempilsticks
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 outlet coolant pipe, located between the thermostat housing and the
inlet radiator hose (1).
Tools Required
- Use a tempilstick in order to find the opening and the closing temperatures
of the coolant 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). |
- Replace the coolant thermostat if it does not operate properly between
this temperature range.
