Parts for your 2015 Subaru Impreza-Manifold gasket

2015 Subaru Impreza manifold-gasket — what it does and when to replace it

Based on technical references, a manifold-gasket is absolutely used on the 2015 Subaru Impreza. The Subaru Factory Service Manual for 2015MY Impreza (STIS) specifies intake and exhaust manifold gaskets as replace-once-removed items in the Intake and Exhaust sections. The Subaru parts catalogue (Group 14 Intake, Group 44 Exhaust) lists both intake manifold-gaskets and exhaust manifold-gaskets for the FB20 2.0L engine. Aftermarket catalogues such as Fel‑Pro and Permaseal also publish matching intake and exhaust manifold-gasket part numbers for 2012–2016 Impreza FB20 applications.

On the 2015 Impreza, the manifold-gasket has a simple job with big consequences: it seals the join between the manifold and the cylinder head. There are two places this matters — the intake side (keeping unmetered air out so the fuel trims stay happy) and the exhaust side (keeping hot gases in the system so the O2 sensors and cat work properly). When these gaskets harden, get pinched, or the manifold is refitted without new ones, the engine can end up running lean, idling rough, or blowing a noisy exhaust leak that smells and ticks under load.

They’re not a scheduled replacement item, but they are a “must replace” any time an intake or exhaust manifold is removed. Best practice for servicing a 2015 Impreza is to inspect the manifold-gasket areas at major services or whenever chasing drivability issues. Look for black sooty tracks at exhaust flanges, a sharp tick on cold start, or a hissing sound and P0171 lean codes from the intake side.

• Use quality OEM or reputable aftermarket gaskets (multi‑layer steel or graphite-faced types are common).
• Ensure both mating surfaces are clean, flat, and free of old material — no sealant unless the service manual explicitly calls for it.
• Refit hardware in the factory sequence and torque to Subaru specs