Subaru Thermostat - STI 04+ Gates making the device waterproof and

making the device waterproof and safe to wash

and rapid heat dissipation

Replace when dirty to maintain peak performance power

while remaining completely rigid

bored and honed to 86

Subaru Thermostat - STI 04+ Gates making the device waterproof andCooling System Repair or ReplaceIf your thermostat has failed, it can stick open or stick closed. A thermostat that's stuck closed will result in an overheat that happens after the engine has been running for a few minutes. If it's stuck open, the engine will never reach proper operating temperature. Both can do long term damage to the engine in your 2018 Subaru STI, so contact a Subaru technician.