Parts for your 2019 Mitsubishi Eclipse cross-Thermostat housing

2019 Mitsubishi Eclipse Cross Thermostat Housing

Yes, a thermostat housing is absolutely used on the 2019 Mitsubishi Eclipse Cross. Technical sources including the Mitsubishi Motors service manual for the GK-series (Cooling System section), the Mitsubishi ASA electronic parts catalogue for the 1.5L turbo 4B40 engine, and common aftermarket catalogues (e.g., Gates/Stant and dealer parts listings) all show a dedicated thermostat and water outlet assembly mounted on the cylinder head, feeding the upper radiator hose. That makes the thermostat housing a relevant, serviceable part on this model.

The thermostat housing’s job is to hold the thermostat in the coolant circuit and route coolant from the engine to the radiator at the right time. On the Eclipse Cross, it’s a compact moulded housing that seals with an O-ring and typically carries a temperature sensor and hose connections. Until the engine warms up, the thermostat stays closed to speed heat-up, once target temperature is reached, it opens and the housing directs flow to the radiator to keep temps stable, cabin heat consistent, and emissions under control.

There’s no fixed replacement interval in the logbook just for the housing, but it’s smart to keep an eye on it whenever coolant is serviced. Common red flags include coolant seepage or crusty residue around the housing, a sweet smell under the bonnet, slow warm-up or poor heater performance (thermostat stuck open), overheating or rapid temp spikes (stuck closed), the radiator fan running too often, or a check engine light with a P0128-style code. Age, heat cycles, or using the wrong coolant can harden seals and make the plastic brittle over time.

When replacement is needed, go with a genuine or quality equivalent housing/thermostat and a fresh O-ring. Work only on a stone-cold engine, catch and dispose of old coolant responsibly, and avoid prying on hose stubs. Clean the mating surface, seat the new seal properly, and tighten fasteners evenly to spec to avoid warping or cracks. Refill with Mitsubishi-approved Super Long Life Coolant (blue), or an equivalent that meets the spec, if using concentrate, mix with demineralised water. Bleed the system carefully with the heater on full hot, top up the reservoir after the first drive, and check for weeps around the housing and hose clamps. Done right, the Eclipse Cross will hold temperature beautifully and go the distance.

Where is the thermostat housing on a 2019 Eclipse Cross?

It’s bolted to the cylinder head on the transmission side of the engine bay, at the end of the upper radiator hose. Follow the top hose back from the radiator and you’ll land on the housing.

Do I have to replace the whole housing, or just the thermostat?

Many Eclipse Cross units use an integrated thermostat-and-housing assembly with a dedicated seal. If the housing is plastic and aged, replacing the complete unit is the safer play. If the housing is sound and not warped, some suppliers offer the thermostat and seal separately.

What coolant should be used after replacing the housing?

Use Mitsubishi Super Long Life Coolant (blue) or a compatible equivalent that meets the same spec. If it’s concentrate, mix 50/50 with demineralised water. Always bleed the system to clear air and recheck the level after the first heat cycle.