Parts for your 2020 Mitsubishi Eclipse cross-Thermostat

2020 Mitsubishi Eclipse Cross Thermostat — Purpose, Care, and When to Replace

According to Mitsubishi technical sources—the Eclipse Cross Workshop Manual (Cooling System section, Group 14) and the Mitsubishi Electronic Parts Catalogue (ASA/EPC) for the 1.5L MIVEC turbo 4B40 engine—the 2020 Mitsubishi Eclipse Cross is fitted with a thermostat assembly. These factory references list a dedicated thermostat and sealing ring within the engine’s cooling circuit, confirming the part is relevant and used on this model year.

For the 2020 Eclipse Cross, the thermostat is the traffic controller of engine temperature. It keeps the engine sitting in its sweet spot—typically in the high-80s to mid-90s °C—by staying shut while the engine warms up and gradually opening to route coolant through the radiator once it’s up to temp. That steady temperature helps fuel economy, engine longevity, emissions, and cabin heater performance, which is especially handy on a frosty Kiwi morning or a brisk Tassie run.

Its home is the thermostat housing, usually where the lower radiator hose meets the engine block near the water pump. The unit is a wax‑pellet, spring‑loaded valve that opens progressively. If it sticks closed, the engine can overheat, if it sticks open, warm‑up drags on and the temp gauge may hover low. The ECU may flag a P0128 code when it suspects the thermostat isn’t helping the engine reach operating temp.

There’s no strict replacement interval for the thermostat on this model, so it’s generally a replace‑on‑condition item. As part of routine servicing, it’s smart to:

• Check for slow warm‑up, fluctuating temps, weak cabin heat, or overheating under load.
• Scan for cooling‑system fault codes (e.g., P0128).
• Inspect for leaks or crusty residue at the thermostat housing.

Preventative replacement can be worthwhile during major cooling work (water pump, housing, hose refresh) or beyond high mileage—think 150,000–200,000 km—especially in harsh climates or stop‑start city use. Always use a genuine or OEM‑quality thermostat and a new O‑ring. Top up with Mitsubishi‑approved Super Long Life Coolant, premixed to the correct ratio, avoid tap water. When refitting, work on a cold engine, drain enough coolant to sit below the housing, refit and torque evenly, then bleed air with the heater on hot and the fan low. After a good drive cycle, confirm the gauge sits steady at mid and recheck the level over the next few trips. If unsure, a licensed tech can pressure‑test and bleed the system properly under the bonnet, saving headaches and ensuring the turbo 1.5T runs at its favourite temperature.

Popular questions about the 2020 Mitsubishi Eclipse Cross thermostat

Where is the thermostat on a 2020 Mitsubishi Eclipse Cross?
It sits in the thermostat housing where the lower radiator hose joins the engine block, close to the water pump. On many cars it’s accessed from the top after removing the engine cover and intake ducting, though sometimes it’s easier from underneath once the undertray is off.

What are the signs the thermostat needs replacing?
Common giveaways include slow warm‑up, a temp gauge that won’t reach or hold centre, weak cabin heat, overheating in traffic or on hills, and a stored P0128 code. You might also see coolant seepage around the housing or notice the radiator fans cycling oddly.

How often should the thermostat be changed?
There’s no fixed schedule. Replace it if it’s faulty or when tackling bigger cooling jobs. Follow the owner’s manual for coolant change intervals—fresh coolant helps the thermostat live a long, easy life. As a preventative step in tough conditions, many workshops consider replacement somewhere after 150,000 km.