Over time, your original expansion tank cap can lose its seal. Because your cooling system is under so much pressure, this can become a messy situation and eventually lead to overheating.
This cap is only intended for the coolant expansion tank, found on all turbocharged EJ motors.
Fits all 2002-2014 Subaru WRX, and 2004+ WRX STI, including 2015+ STI.
