Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Cooling System (H4DO): Thermostat: Inspection
- Check that the thermostat does not have deformation, cracks or damage.
- Check that the thermostat valve closes completely at an ambient temperature.
- Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and check the temperature and valve lift when the valve begins to open and when the valve is fully opened. Replace the thermostat if faulty.NOTE:
- During the test, agitate the water for even temperature distribution.
- Leave the thermostat in the boiling water for five minutes or more before measuring the valve lift.
- Hold the thermostat with a wire or the like to avoid contacting with container bottom.
Starting temperature to open:
Engine side
90 - 94°C (194 - 201°F)
CVTF cooler (with warmer feature) side (CVT model)
48 - 52°C (118 - 126°F)
Full open temperature:
Engine side
100°C (212°F)
CVTF cooler (with warmer feature) side (CVT model)
63°C (145°F)
Total valve lift:
Engine side
8.0 mm (0.315 in) or more
CVTF cooler (with warmer feature) side (CVT model)
6.0 mm (0.236 in) or more
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.