Cap
| WARNING | Never remove the pressure relief cap while the engine is operating or hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure that all the pressure has been released, (with a cloth) remove the pressure relief cap. |
- Remove the pressure relief cap from the degas bottle.
- Immerse the pressure relief cap in water and install it on the shallow filler neck of the Radiator/Heater Core Pressure Tester and Radiator Cap Adapter, part of the Radiator/Heater Core Pressure Tester.
- Immerse the filler neck seal in water and install it in the filler neck adapter.
- Install the filler neck adapter with the filler neck seal to the Radiator Cap Adapter.
- Connect the female quick-connect fitting of the pressure test pump to the male quick-connect fitting of the filler neck adapter.
- Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained.
- Release the pressure by turning the relief screw counterclockwise. Then tighten the pressure relief screw and repeat Step 6 (at least twice) to make sure the reading is repeatable within the specification of the pressure relief cap.
- If the pressure test gauge readings are not within specifications, install a new pressure relief cap. If the pressure test gauge readings are within specifications, carry out the cooling system «PRESSURE TEST»(ref-194047-S26810669832005092600000) .
Thermostat
A new thermostat should be installed only after the following electrical and mechanical tests have been carried out.
Thermostat - Electrical Test
Note. The electrical thermostat test is most accurate if carried out indoors at less than 37.8°C (100°F) ambient air. This test may be carried out with or without the hood open and with the engine warm or cold.
Scheme 40
- Check the engine coolant level. Fill as needed.
- With the ignition OFF, voltage values (0-5 V) may now be monitored while the sensor retains its connection to the wiring harness. A scan tool may be used to monitor the ECT on vehicles equipped with data link connector (DLC). The SBDS sequence to use for the screen is: Toolbox-Electronic Engine Control and DCL-Item.
- Place the transmission in PARK (P) or NEUTRAL (N).
- Start the engine and allow the engine to idle throughout this test. Allow the engine to run for two minutes, then record the ECT voltage. Record the ECT voltage every 60 seconds. When the ECT voltage trend changes direction or only changes slightly (0.03 volt or less) from the previous reading, record this as the thermostat opening voltage. Use the voltage and corresponding coolant temperature chart listed below.
- If the thermostat opening voltage is greater than 0.58 volt and less than 90°C (194°F), install a new water thermostat.
- If the thermostat opening voltage is less than 0.58 volt and greater than 90°C (194°F), the thermostat is good and a new thermostat should not be installed. GO to «SYMPTOM CHART»(ref-194047-S32252485772005092600000) for further instructions.
Thermostat - Mechanical Test
- Remove the thermostat.
- Check the thermostat for seating. Hold the thermostat up to a lighted background. Leakage of light around the thermostat valve at room temperature indicates that a new thermostat should be installed. Some thermostats have a small leakage notch at one location on the perimeter of the thermostat valve, which is considered normal.
- Immerse the thermostat in a boiling antifreeze and water mixture.
- See «GENERAL SPECIFICATIONS»(ref-194047-S19786367682005092600000) for thermostat opening temperatures.