COBB AIR/OIL SEPARATOR FOR FORD FOCUS ST 2013-2018

The COBB Air/Oil Separator for the 2013–2018 Ford Focus ST is designed to protect your EcoBoost engine by keeping oil vapor out of the intake system. Developed entirely in-house over several years, this AOS system enhances performance and reliability without compromising emissions compliance.

Due to the tight packaging of Ford’s EcoBoost layout, COBB engineered a custom spacer plate made from 33% glass-filled nylon—precision injection molded for perfect fitment. This plate installs between the OEM air/oil separator and the engine block using a COBB-supplied OEM gasket, ensuring a secure, leak-free seal. The billet aluminum canister connects to the factory PCV system and routes crankcase vapors through a swirl pot and a series of internal baffles, forcing oil particles to condense into liquid.

Thanks to an integrated drain-back line, the collected oil automatically returns to the crankcase—eliminating the need to manually empty the unit. This process keeps intake valves cleaner, helps prevent detonation, and preserves the octane rating of your fuel.

The system features a bright black dip-anodized finish, a laser-etched COBB logo, and added baffling both in the plate and canister. It's a smart, long-term upgrade for any Focus ST owner looking to maintain peak engine health and performance.

Note: Installation of this AOS requires a Sound Symposer Delete. If you don't already have one, check out the COBB Sound Symposer Delete Kit.

This product is 50-state legal with California Air Resources Board (CARB) EO# D-660-123, making it fully emissions-compliant.