Parts for your 2017 Subaru Exiga-Thermostat housing

2017 Subaru Exiga thermostat housing — purpose, service tips, and FAQs

The 2017 Subaru Exiga (also sold as the Crossover 7 in Japan) does use a thermostat housing. Technical references from Subaru’s Factory Service Manual (Engine Cooling section) and the Subaru FAST electronic parts catalogue for the YA-platform Exiga list the thermostat and “water inlet” (thermostat housing) as a bolted assembly on the front of the engine, at the lower radiator hose connection. This applies to the FB25-powered 2017 model and earlier EJ-equipped variants, confirming the part is definitely fitted and relevant to servicing.

The thermostat housing’s job is to hold the thermostat securely, direct coolant flow into the water pump, and provide a sealed joint to the lower radiator hose. Together with the thermostat, it helps the engine warm up quickly and then stay bang-on at operating temperature, which keeps fuel economy tidy and protects the engine on long Kiwi and Aussie drives alike.

During regular servicing, it’s smart to check the housing area for crusty white or pink residue, dampness, or a sweet coolant smell under the bonnet. Many Exiga housings are a composite/plastic or cast alloy unit, either way the O-ring or gasket should be replaced any time the thermostat is removed. Subaru’s long-life coolant intervals are generous, but every coolant change is a great time to inspect the housing, hose clamp and lower hose condition.

If the cabin heater’s gone weak, the temp gauge is wandering, the engine runs too cool on the open road, or it’s spiking hot in traffic, the thermostat may be sticking. A warped or cracked housing can also cause slow leaks that only show up after parking. When replacing, use a quality (ideally genuine-spec) thermostat and new seal, and fit the thermostat in the correct orientation as per the service manual. Refill with the correct Subaru-compatible coolant, bleed the system thoroughly (nose-up helps), run the heater on hot, and recheck the level after a decent drive. Avoid overtightening the housing bolts—light, even torque is the go—to prevent cracking or warping. Keeping this small part happy goes a long way to keeping the Exiga’s flat-four cool, efficient, and ready for another big kilometre haul.

• Tell-tales of trouble: temp gauge swings, poor heater output, visible weep at the housing, or repeat low-coolant top-ups.
• Best practice: new thermostat + new O-ring/gasket, correct coolant, careful bleeding, and a check of the lower hose and clamp.

Popular questions about the 2017 Subaru Exiga thermostat housing

Where is the thermostat housing on a 2017 Subaru Exiga?
It’s mounted low at the front of the engine where the lower radiator hose connects—Subaru labels it the “water inlet.” The thermostat sits inside this housing, bolted to the water pump area. Expect a tight spot to access from below with the undertray off.

Do you replace just the thermostat, or the housing as well?
Normally, the thermostat and O-ring are replaced, while the housing is reused if it’s not cracked or warped and the sealing face is clean. If there’s any damage, distortion, or corrosion, replace the housing too—cheap insurance against leaks.

What are common signs the thermostat or housing needs attention?
Slow warm-up, fluctuating temperature, overheating in traffic, poor heater performance, or visible coolant residue near the lower hose are common. A pressure test can confirm small leaks around the housing before they become bigger dramas.