Parts for your 2017 Subaru Impreza-Manifold gasket

2017 Subaru Impreza manifold gasket: what it does and when to replace it

Referencing the Subaru Service Manual for the 2017MY Impreza (FB-series engine, Intake and Exhaust Manifold sections) and the Subaru genuine parts catalogue for the GK/G4 chassis, the vehicle absolutely uses manifold gaskets. There are intake manifold gaskets sealing the plastic intake to each cylinder head, and exhaust manifold gaskets sealing the headers to the heads. So a manifold-gasket is relevant and fitted to the 2017 Subaru Impreza.

On this 2.0‑litre FB engine, manifold gaskets do a quiet but critical job. Intake manifold gaskets keep unmetered air out so the engine can hold a steady idle, maintain the right fuel trims, and start cleanly on cold mornings. Exhaust manifold gaskets keep hot exhaust gas in the pipes so the oxygen sensors read accurately, the cat warms up properly, and there’s no sooty blow-by or ticking on cold start. Subaru uses moulded rubber-style gaskets on the intake (seated in the manifold runners) and multi‑layer steel on the exhaust to cope with heat and movement—especially important on a boxer engine with two cylinder heads.

They’re not a scheduled service item, but they should be replaced any time the intake or exhaust manifold is removed, or if there are leak symptoms. Common tells include:

• Intake leak: rough idle, high long-term fuel trims, a hiss near the manifold, or a lean-code check engine light.
• Exhaust leak: a sharp tick on cold start that softens when warm, fumes near the front of the car, or black soot at the flange.

When servicing, always clean the sealing faces, use new gaskets, and follow the factory torque sequence and specs. The intake bolts are tightened in stages across each runner to avoid warping the plastic manifold