Thermostat Test
- Remove the thermostat from the vehicle. Refer to «Thermostat Removal and Installation»(ref-257072-S27312867782007062900000) .
- Make sure the valve spring is tight when the thermostat is fully closed. If the spring is not tight, replace the thermostat.
- Suspend the thermostat and a thermometer in a pan of 50/50 mixture of ethylene glycol and water. Do not let the thermostat or the thermometer rest on the bottom of the pan because the uneven concentration of heat on the bottom could result in inaccurate temperature measurements.
- Heat the pan on a burner.
- Use the thermometer to measure the temperature of the heated solution.
- The thermostat should begin to open at 87 °C (189 °F) and it should be fully open at 102 °C (216 °F). If it does not open at these temperatures, replace the thermostat.
Surge Tank Cap Test
Tools Required
KM-471 Adapter
The surge tank cap maintains proper pressure, protects the system from high pressure by opening a pressure valve, and protects the coolant hoses from collapsing because of a vacuum.
Scheme 3
- Wash any sludge from the surge tank cap and the valve seat of the vacuum pressure valve for the surge tank cap.
- Check for any damage or deformity to the vacuum pressure valve for the surge tank cap. If any damage or deformity is found, replace the cap.
- Install a suitable cooling system pressure tester to the cap using the adapter KM-471.
- Pull the vacuum pressure valve open. If the surge tank cap does not seal properly, replace the surge tank cap.
- Pressurize the cap to 90 - 120 kPa (13.1 - 17.4 psi).
- Wait 10 seconds and check the pressure held by the tank cap tester.
- If the pressure held by the cooling system pressure tester falls below 80 kPa (11.6 psi), replace the surge tank cap.