Subaru Forester Thermostat Malaysia

The Subaru Forester SJ (2013–2018) and SK (2019+) are popular AWD SUVs in Malaysia using the FB25 2.

Subaru Forester Thermostat

Forester FB25 thermostat: wax element thermostat opens at 88°C; controls coolant flow to radiator; lifespan 150,000+ km; failure mode is usually stuck open (engine runs cold) — never stuck closed (overheating) on modern units
Forester thermostat stuck open: if Forester takes very long to warm up (temperature gauge stays below midpoint), or heater blows cool air — suspect thermostat stuck open; this reduces fuel economy and oil performance; replace thermostat
Forester thermostat housing: plastic thermostat housing on FB25 can crack at high mileage — look for coolant stain or drip near thermostat housing; replace housing and thermostat together if housing is cracked
Forester thermostat replacement: straightforward job on FB25; drain partial coolant; remove housing; fit new thermostat with new gasket; refill with Subaru SLLC coolant; bleed air from cooling system; check for leaks after first heat cycle