Collection: Subaru Dual Chamber Air Oil Separator (V3) AOS Kits

The V3 is Crawford's dual-chamber air/oil separator. It pulls oil out of the crankcase air before that air reaches the intake, and returns the oil to the pan. The intake, intercooler, and combustion chambers stay cleaner, and the oil stays in the engine where it belongs. Read the original guide: All about Subaru's Original Air Oil Separator & Why You Need One.

Crawford developed the original closed-loop Subaru AOS. The V3 is the current version of that design: two separation chambers, and it keeps your factory PCV valve in place. There is nothing to drain and nothing to empty — the system is closed-loop and maintenance-free.

Crawford is the original, and everyone else is a copy. Our aluminum construction weighs less than the competitors' heavy cast design, and the cast weight has no benefit over ours. Every Crawford AOS is made in the USA with USA components. The competitors make theirs in China.

Kits are vehicle-specific, with brackets and hoses for the application: WRX, STI, Forester XT, Ascent, and BRZ / FR-S / 86. Confirm your year and intercooler setup on the product page before you order.

Every V3 carries Crawford's limited lifetime warranty.