For detailed thermostat diagnostic procedures. Refer to
Cooling System Diagnostic System Check
.
Thermostat Test
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.
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. |
| • | J 24731 -206
tempilstick melts at 97°C (206°F). The thermostat should be fully
open. |
- Replace the coolant thermostat if it does not operate properly
between this temperature range.
