Parts for your 2012 Subaru Impreza-Manifold gasket

2012 Subaru Impreza manifold gasket — what it does and when to replace it

Based on technical sources, a manifold gasket is absolutely relevant and used on the 2012 Subaru Impreza. The Subaru Factory Service Manual for the 2012 Impreza (via Subaru’s Technical Information System) details intake and exhaust manifold removal/installation procedures and calls for gasket replacement during reassembly. Subaru’s genuine parts catalogue for the FB20 engine lists both intake manifold gaskets and exhaust manifold gaskets, and major aftermarket catalogues also carry direct-fit gasket sets for this model. So yes — the 2012 Impreza is fitted with manifold gaskets from factory.

On a 2012 Impreza, manifold gaskets are the thin but vital seals that sit between the intake manifold and the cylinder heads, and between the exhaust manifold (headers) and the heads. Their job is to keep everything sealed so the engine can breathe properly and the exhaust can exit cleanly. Intake gaskets prevent unmetered air sneaking into the engine (which would throw the air–fuel mix lean), while exhaust gaskets stop hot gases, noise, and soot from escaping at the flanges.

Over time, heat cycles, vibration, and previous disassembly can flatten or crack a gasket. When that happens, drivers might notice a rough idle, a whistle or hiss under the bonnet, a ticking on cold start, lean fault codes, or a whiff of exhaust under load. Fuel economy can slip, and there may be black sooting around the exhaust manifold flange.

As part of routine servicing, it’s smart to do a quick check for leaks. Under the car when cold, look and listen around the exhaust manifold area for ticking and sooty traces. Up top, a workshop smoke test is the safest way to spot intake leaks. Any time a manifold is removed — say, for injector work or an exhaust upgrade — new gaskets should go in. Clean the mating surfaces, use quality OEM-equivalent gaskets, and tighten fasteners in the factory sequence to the specified torque in the Subaru manual. No extra sealant is normally required unless the service information explicitly says so.

There’s no fixed replacement interval, it’s done on condition. Many last well past 150,000 km, but once a leak starts, don’t put it off. A leaking intake gasket can lead to poor running and codes, while an exhaust leak can cook nearby components and affect oxygen sensor readings. DIY-savvy owners can tackle it with the right tools and torque specs, but plenty will prefer a trusted mechanic to handle it.

• Typical signs to watch for: rough idle, hissing or ticking noises, fuel trims/lean codes, exhaust smell in the cabin, sooty marks at flanges.
• Best practice: replace gaskets whenever manifolds come off, follow Subaru torque specs and patterns, inspect studs and nuts and replace if corroded.

Popular questions about the 2012 Subaru Impreza manifold gasket

Does the 2012 Impreza have both intake and exhaust manifold gaskets?
Yes. The FB20 engine in the 2012 Impreza uses intake manifold gaskets between the manifold and cylinder heads, and exhaust manifold gaskets between the headers and heads. Both are service items and should be renewed whenever the manifolds are removed.

What are the common symptoms of a failing manifold gasket on this model?
For intake gaskets: rough or high idle, a hissing sound, lean fault codes, and reduced fuel economy. For exhaust gaskets: a ticking noise on cold start that gets quieter warm, exhaust smells, and black soot around the flange area. If any of these appear, a smoke test (intake) or visual/aural check (exhaust) can confirm a leak.

Should sealant be used when installing new manifold gaskets?
Generally, no. Quality gaskets are designed to be installed dry on clean, flat surfaces. Follow the Subaru Factory Service Manual for torque specs and tightening order. Only use sealant if Subaru’s service information specifically calls for it at a given joint.