Subaru Thermostat - STI 04+ Gates RAYS logo and the 57

RAYS logo and the 57 mark is embossed onto the spoke

and rapid heat dissipation

bored and honed to 86

and most builds are under 800HP so we decided to make a direct bolt in axle that will support 800WHP

Subaru Thermostat - STI 04+ Gates RAYS logo and the 57Cooling 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.