Parts for your 2013 Subaru Impreza-Manifold gasket

2013 Subaru Impreza manifold-gasket — what it does and when to replace it

Yes, the 2013 Subaru Impreza uses manifold gaskets — both intake manifold gaskets and exhaust manifold gaskets. This is documented in Subaru’s factory Service Manual for the GJ/GP series (engine section for FB20), the Subaru Technical Information System (STIS), and dealer parts catalogues that list separate intake-manifold and exhaust-manifold gaskets for 2012–2016 Impreza models. Turbo variants in the broader Impreza/WRX family also specify exhaust manifold and up-pipe gaskets in the same sources.

On a 2013 Impreza, the manifold gaskets seal two critical junctions: the intake manifold gasket keeps unmetered air from sneaking into the engine, and the exhaust manifold gasket keeps hot exhaust gases from leaking out before the catalytic converter. When these seals are healthy, the car idles smoothly, runs efficiently, and keeps emissions and noise in check. When they’re crook, you’ll chase rough idle, lean fuel trims, a noisy tick from the headers, or a bit of sooty staining near the flange.

As a servicing tip, manifold gaskets are considered single-use on this Subaru. Any time the intake or exhaust manifold comes off — say for spark plugs on some engines, valve cover work, or header removal — fresh gaskets should go back in. Genuine or high-quality aftermarket multi-layer steel (MLS) or composite gaskets are worth the few extra dollars, and proper torque in the factory sequence helps them bed in and stay sealed.

• Typical symptoms of intake leaks: high or wandering idle, pinging, poor fuel economy, and codes like P0171 (system too lean).
• Typical symptoms of exhaust leaks: ticking on cold start, fumes in the engine bay, sluggish low‑down torque, and oxygen sensor adaptation swings.
• Good practice: inspect flange faces for warping, clean with plastic or brass tools (not gouging alloy), and check studs/nuts for corrosion.

There isn’t a strict kilometre-based interval just for gaskets, but during scheduled services it’s smart to give the intake and exhaust junctions a quick once-over. If there’s staining, a whiff of exhaust under the bonnet, or a hiss you can trace with a bit of soapy water (intake) while the engine idles, it’s time to organise replacement. On the FB20 Impreza, many DIYers can handle intake gaskets in an afternoon with basic spanners