Parts for your 2020 Mitsubishi Asx-Thermostat housing

2020 Mitsubishi ASX Thermostat Housing — What It Does and When to Replace It

Yes, the 2020 Mitsubishi ASX uses a thermostat housing. Technical sources confirm this: the Mitsubishi Motors workshop manual for ASX/RVR/Outlander Sport (MY2020) in the Cooling System section depicts a thermostat and housing (“water outlet”) at the cylinder head outlet, the Mitsubishi ASA electronic parts catalogue lists a thermostat/thermostat housing assembly for GA2W/GA6W 2020 ASX variants, and common parts catalogues used in AU/NZ (including dealer EPC extracts and aftermarket listings) supply complete thermostat-housing assemblies for the 2.0L MIVEC petrol. That makes thermostat-housing relevant for servicing and repairs on a 2020 Mitsubishi ASX.

On the 2020 ASX, the thermostat-housing (often called the water outlet) is the little hub that directs coolant from the engine to the radiator and holds the thermostat and sealing O-ring. It also commonly carries the engine coolant temperature sensor. Its job is simple but vital: help the engine warm up quickly, then keep it in the sweet spot for efficiency and longevity. When the engine’s cold, the thermostat stays shut so it heats up faster, once it’s at operating temp, it opens to let coolant flow through the radiator.

As part of regular servicing, the housing and associated hoses are worth a look whenever coolant is changed. On many ASX engines the housing is a moulded composite, which is light and efficient, but over years and heat cycles it can warp, crack, or seep at the O-ring groove. If the vehicle has racked up higher kilometres, or there’s evidence of past overheating, proactive replacement of the thermostat and housing assembly can save grief later.

• Tell-tales it’s time: slow warm-up or running too cool, fluctuating temp gauge, visible coolant crust around the housing, a sweet coolant smell after a drive, or dribbles under the front of the car.

Replacement is straightforward for a competent home mechanic: work on a stone-cold engine, drain enough coolant to sit below the housing, disconnect the upper hose and sensor plug, unbolt the housing, and swap in a new thermostat and O-ring. Clean the mating surface, fit the new seal dry (unless the service manual specifies otherwise), and tighten the bolts evenly to factory spec. Refill with Mitsubishi Genuine Super Long Life Coolant (blue) or an equivalent that meets the right spec, bleed air from the system, then verify hot heater output and steady operating temperature on a test drive.

There’s no hard-and-fast interval to replace the thermostat-housing, it’s typically done on condition. Many workshops suggest inspecting it at each coolant service and replacing it at the first sign of leakage, sticking thermostat behaviour, or when doing related cooling work (water pump, major hose replacement), to keep the ASX happy across Aussie and Kiwi conditions.

Popular questions about the 2020 Mitsubishi ASX thermostat-housing

Where is the thermostat-housing located on a 2020 ASX?
It sits at the cylinder head’s upper coolant outlet, near the upper radiator hose connection. Follow the top radiator hose back to the engine and you’ll land right on the housing, which also typically carries the coolant temp sensor plug.

Is the factory housing plastic or alloy?
Depending on engine variant and market, the ASX commonly uses a moulded composite (plastic) housing, while some applications or aftermarket replacements are aluminium. Either style is fine when quality parts are used, the key is a fresh thermostat and O-ring, correct torque, and proper bleeding.

Do you have to bleed the cooling system after replacing it?
Yes. After refilling with the correct coolant mix, run the engine with the heater on full hot and the cap at the specified point (per the manual) to purge air. Many workshops use a vacuum filler to avoid air pockets. Confirm steady operating temperature, no gurgling, a hot heater, and full reservoir at the correct mark once cooled.