The OEM plastic breather/coolant fitting can start to leak over time, or worse, break when you’re trying to remove/replace lines during a build or an AOS install. It can also crack internally, leading to cross-contamination of coolant and oil. (That’s bad!) We typically replace these at the same time as replacing the PCV valve.
Fits all 2013+ Subaru BRZ/Scion FR-S/Toyota GR86, and 2015-2016 Subaru WRX.
