Parts for your 2018 Mitsubishi Eclipse cross-Thermostat

2018 Mitsubishi Eclipse Cross Thermostat — What It Does and When to Replace It

A thermostat is absolutely relevant and fitted to the 2018 Mitsubishi Eclipse Cross. Technical references confirm this: Mitsubishi Motors service information for the Eclipse Cross (GK, 2018 model year, Group 14 – Cooling) details the thermostat within the engine’s cooling system, and the Mitsubishi ASA parts catalogue lists a thermostat assembly and seal for the 1.5L turbo-petrol 4B40 engine. That means this model relies on a conventional coolant thermostat to manage engine temperature.

On the Eclipse Cross, the thermostat’s job is to let the engine warm up quickly, then hold it in the sweet spot for efficiency, performance, and emissions. It stays closed on cold start to speed warm-up, then opens to route coolant through the radiator once operating temperature is reached. If it sticks open, the engine can run cool, burn more fuel, and feel a bit sluggish, if it sticks shut, it can overheat—never good news.

Thermostats aren’t typically a scheduled replacement item, but they are worth attention as kilometres rack up or when cooling system work is being done. During regular servicing, a technician will usually check for symptoms that point to thermostat trouble:

• Slow warm-up or the temp gauge sitting lower than normal on the open road
• Overheating in traffic or after a short drive
• Heater not blowing hot when it should
• Fans running excessively or temperature swings

Best practice when replacing the thermostat on a 2018 Eclipse Cross is to use a genuine or quality OEM-spec unit with the correct temperature rating and a new O-ring/gasket. The thermostat housing is mounted on the engine block (near the water pump area), so access varies a bit with drivetrain layout. Always start with a cold engine, capture and dispose of coolant responsibly, and refill with the correct Mitsubishi-approved long-life coolant. After installation, bleed the system to clear air pockets, then heat-cycle the engine and verify stable temperature, hot cabin heat, and no leaks.

As preventative care, stick to the coolant change intervals, keep the correct mix ratio, and inspect hoses and the housing for age-related cracks. If the cooling system has been contaminated or a water pump has failed, replacing the thermostat at the same time is sensible insurance.

Popular questions

Does the 2018 Eclipse Cross definitely have a thermostat?
Yes. Mitsubishi’s 2018 Eclipse Cross (1.5L turbo) uses a conventional engine coolant thermostat documented in factory service literature and listed as a service part. It’s a normal, essential component of the cooling system.

How often should the thermostat be replaced?
There’s no strict interval, replace it if there are symptoms or when major cooling work is done (e.g., water pump or radiator replacement), or at high kilometres as preventative maintenance. Always renew the seal and use the correct coolant afterwards.

Where is it located, and can a DIYer replace it?
The thermostat sits in a housing on the engine near the water pump. A competent DIYer can handle it with patience, the right tools, and the correct service procedure for draining and bleeding coolant. If unsure, a qualified workshop is the safer bet.