Ranger 2WD L4-153 2.5L SOHC VIN C SFI (1998)
Thermostat: Testing and Inspection
Thermostat Test
1. Remove the water thermostat.
2. Check the water thermostat for seating. Hold the water thermostat up to a lighted background. Leakage of light around the thermostat valve at
room temperature indicates that the water thermostat should be replaced. Some water thermostats have a small leakage notch at one location on the
perimeter of the thermostat valve, which is considered normal.
3. Immerse it in a boiling antifreeze and water mixture.
4. See General Specifications Table for the water thermostat opening temperatures.
