Parts for your 2017 Subaru Xv-Thermostat housing

2017 Subaru XV Thermostat Housing: what it does, where it lives, and how to look after it

Per Subaru’s technical literature, the 2017 Subaru XV (FB20 2.0L petrol) absolutely uses a thermostat housing. The Subaru Global Service Manual for the FB-series cooling system shows the thermostat fitted at the water pump inlet and retained by a “water inlet/thermostat cover” (i.e., the housing). Subaru’s FAST electronic parts catalogue for the 2017 XV also lists this water inlet/cover as a separate service part. So, yes—thermostat-housing is relevant to the 2017 Subaru XV.

On this XV, the thermostat housing sits low on the engine at the end of the lower radiator hose. It encloses the thermostat, seals coolant with an O-ring, and provides a neat passage for coolant to enter the engine. The housing’s job is simple but critical: keep the thermostat properly located and sealed so the engine warms up quickly, then holds a stable operating temperature for efficiency, performance, and engine longevity.

Owners thinking about maintenance should treat the thermostat housing as part of the cooling system’s regular care. If the car is running cool or hot, taking ages to warm up, or weeping coolant around the lower hose area, the housing, O-ring, or thermostat may be due for attention. A housing that’s corroded, pitted at the sealing face, or cracked won’t hold pressure or fluid properly and should be replaced.

When replacing the thermostat or the housing, it’s smart to refresh the O-ring and coolant at the same time. Follow the service manual steps under the bonnet: drain the coolant safely, remove the lower hose, unbolt the housing, clean the mating surfaces, and fit a genuine-spec thermostat with a new seal. Refit the housing, torque the bolts to the factory spec, reattach the hose, then refill and bleed the cooling system to purge air. After a short drive, recheck the coolant level and inspect for any drips around the housing.

• Watch for symptoms: slow warm-up, temperature swings, low heater output, or coolant traces near the lower hose.
• Use the correct Subaru-spec coolant and a new O-ring whenever the housing is disturbed.
• If the housing face is damaged or the neck is distorted, replace the housing rather than trying to re-seal it.

Done right, the XV’s thermostat housing will stay leak-free and help the engine run right on temperature, kilometre after kilometre.

Popular questions

Where is the thermostat housing on a 2017 Subaru XV?
It’s mounted low on the engine at the lower radiator hose connection, on the water pump inlet side. Under the vehicle or from above with the intake ducting out of the way, it’s the alloy “water inlet/thermostat cover” that holds the thermostat and O-ring.

Should the thermostat housing be replaced with the thermostat?
Not always, but it’s recommended if the sealing face is pitted or the neck is damaged. At minimum, fit a new O-ring and thermostat. If there’s corrosion or warping, a new housing saves headaches and keeps the cooling system sealed.

What coolant should be used after housing or thermostat work?
Use the Subaru-specified long-life coolant compatible with the FB-series engine. Mixing types can reduce corrosion protection and shorten service life, so stick with the correct spec and bleed the system properly after refilling.