Engine Coolant Thermostat + Sealing Gasket for Subaru

Keep your boxer engine at the ideal temperature with this OE-spec thermostat and gasket set. It stabilizes coolant temperature for smooth power, lower fuel use, cleaner emissions, and longer engine life. The gasket forms a leak‑tight seal, preventing coolant loss and air entry.

How it works

Inside is a wax‑pellet valve calibrated to open at a precise temperature. When coolant heats up, the wax expands and lifts the valve, sending flow to the radiator. When cold, it stays shut to speed warm‑up and ensure strong cabin heat. The molded ring gasket seals the housing, keeping pressure and flow correct.

Why you need it ️

Correct temperature control protects head gaskets, avoids hot spots, and keeps fan cycles normal. Faster warm‑up improves drivability and reduces wear. Perfect fit replaces tired units during cooling system service or after a P0128 warning.

If the part fails ⚠️

Stuck closed: rapid overheating, boiling coolant, warped heads. Stuck open: cold running, high fuel use, weak heater, MIL on (P0128). Leaking or crushed gasket: coolant drip, air pockets, corrosion, unstable gauge. Replace and bleed coolant for best results .

Compatibility

• Impreza
• Forester
• Exiga