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, a cross-pattern snug, then final torque, helps prevent warping.
• After intake work, smoke-test for vacuum leaks and clear trims, after exhaust work, check for leaks once the system is heat-cycled.

Owners will appreciate that a fresh manifold-gasket often restores a smoother idle, cleaner fuel economy, and a quieter cabin. It’s a straightforward, inexpensive part that protects much pricier components — worth doing right the first time.

Does a 2015 Subaru Impreza have a manifold-gasket?

Yes. The FB20 engine uses intake manifold-gaskets between the intake runners and the cylinder heads, and exhaust manifold-gaskets between the heads and exhaust headers. Subaru’s 2015MY service manual and parts catalogue both list these gaskets as distinct, replaceable items.

When should the manifold-gasket be replaced on a 2015 Impreza?

Replace it any time the manifold is removed, or if there are symptoms of a leak such as rough idle, lean codes, exhaust ticking, or fumes. While it’s not a time-based service item, inspecting it during major services and whenever manifolds come off is wise.

Is it safe to drive with a leaking manifold-gasket?

Not ideal. An intake leak can cause a lean mix and poor running, an exhaust leak can skew O2 readings, boost emissions, and risk catalytic converter damage. It’s usually safe to limp short distances, but getting it repaired promptly avoids bigger bills.