Parts for your 2022 Mitsubishi Eclipse cross-Thermostat

2022 Mitsubishi Eclipse Cross Thermostat: Purpose, Care, and When to Replace

Based on technical documentation, the 2022 Mitsubishi Eclipse Cross is fitted with an engine coolant thermostat. The Mitsubishi Eclipse Cross Workshop/Service Manual (Group 14 – Cooling) for the 1.5L turbo petrol (4B40) and the PHEV’s 2.4L engine details a wax‑type thermostat in the water outlet. The Mitsubishi ASA electronic parts catalogue for the 2022 GK/GL series also lists a dedicated thermostat assembly and gasket/O‑ring for these engines. So yes, the thermostat is very much a relevant, factory‑fitted component on this model.

That small valve does a big job. It holds coolant back while the engine warms up, then opens at roughly normal operating temperature to circulate coolant through the radiator. The result is quicker warm‑up on cold starts, steadier engine temperature on the move, better fuel economy, cleaner emissions, stronger cabin heat on winter mornings, and reduced engine wear. On PHEV variants, where the petrol engine may cycle on and off, the thermostat helps the engine hit its sweet spot promptly whenever it’s called into action.

While thermostats aren’t usually a scheduled replacement item, they do wear with age, heat cycles, and poor‑quality coolant. Many techs in Australia and New Zealand will recommend replacement proactively during major cooling system work (e.g., water pump or radiator replacement) or around high kilometre/age milestones. Always follow the service schedule in the owner’s manual and use the correct Mitsubishi‑approved coolant mix.

• Symptoms of a dodgy thermostat: slow warm‑up or overcooling, temp gauge wandering, poor heater output, overheating at highway speeds, cooling fans running oddly, check engine light (often P0128).
• Best practice when replacing: fit the correct temp‑rated OEM or quality equivalent thermostat with a new seal, clean the mating faces, torque housing bolts evenly, and never reuse crushed gaskets.
• Bleeding tips: only open the radiator cap when stone cold, set the heater to hot, top up with the specified premix coolant (or demineralised water plus the correct concentrate), run the engine to operating temp, and bleed air as per the workshop procedure. PHEV models may need a scan tool routine to cycle electric pumps/valves for a proper bleed.

A healthy thermostat helps the Eclipse Cross feel crisp in daily driving, protects the engine on long Kiwi and Aussie road trips, and keeps the heater toasty in winter. If there’s any doubt, testing or a preventative swap during cooling system service is cheap insurance.

Where is the thermostat on a 2022 Mitsubishi Eclipse Cross?

It’s typically housed in the thermostat/water outlet assembly where the upper radiator hose meets the engine. On the 1.5L turbo (4B40), look under the bonnet at the engine’s hose junction on the cylinder head side. PHEV models place it similarly near the engine water outlet, separate to the electrified cooling loops.

How often should the thermostat be replaced?

There’s no strict interval in most schedules. Replace it if there are symptoms, if a fault code like P0128 appears, or as preventative maintenance during major cooling work or at high kilometres/age. Using the correct coolant and changing it on time helps the thermostat last longer.

Can a stuck thermostat damage the engine?

Yes. Stuck closed can cause overheating and serious engine damage. Stuck open can lead to overcooling, poor heater performance, increased fuel use, and extra wear. If the gauge behaves oddly or the heater goes cold at speed, get it checked before a long drive.