Parts for your 2017 Subaru Outback-Manifold gasket

2017 Subaru Outback manifold gasket — what it does and when to sort it

Yes, a manifold gasket is absolutely relevant on a 2017 Subaru Outback. Technical sources including the Subaru Factory Service Manual for the 2015–2019 Outback/Legacy (Engine: Intake and Exhaust sections) and the Subaru parts catalogue (FAST/STIS, 2017 Outback, FB25 and EZ36 engines) specify both intake manifold gaskets and exhaust manifold gaskets for this model. These gaskets sit between the manifold flanges and the cylinder heads (and at some junctions further downstream) to keep the engine sealed and happy.

Their job is straightforward but critical. Intake manifold gaskets keep unmetered air from sneaking into the engine, so fuelling stays on target and idle remains smooth. Exhaust manifold gaskets keep hot gases where they belong, preventing ticking leaks, loss of low-end torque, and fumes under the bonnet. On the 2.5L FB25 and the 3.6R EZ36, the intake gaskets are composite moulded seals designed for thermal cycling, while the exhaust manifold gaskets are typically multi‑layer steel to cope with heat and pressure.

There’s no fixed replacement interval in Subaru’s maintenance schedule, these gaskets are generally replaced when disturbed (for example, when removing the intake for spark plugs on the EZ36, or when servicing exhaust hardware), or when symptoms appear. Common signs that point to intake gasket issues include a whistling or hissing noise, rough idle, lean codes (like P0171/P0174), or higher than normal fuel trims. Exhaust gasket leaks tend to sound like a sharp tick on cold start that softens as things warm, plus a sooty trace around the flange or a whiff of exhaust in the engine bay.

• When replacing, use OEM‑quality gaskets and clean the mating faces thoroughly, don’t use sealants unless the manual explicitly calls for them.
• Follow the FSM torque sequence and specs with a quality torque wrench, heat cycles matter, so recheck accessible fasteners after a few short trips.
• Inspect studs, nuts, and heat shields for corrosion, and replace any dodgy hardware. On the FB25, check PCV and vacuum hoses while the intake is off, on the EZ36, give both banks’ flanges equal attention.
• If diagnosis is unclear, a smoke test (intake) or a cold-start stethoscope check (exhaust) usually confirms a leak quickly.

Look after the sealing surfaces and quality gaskets will typically last well past 150,000 kilometres, only needing doing when other work is on the cards or a leak shows up.

Popular questions

Does the 2017 Subaru Outback have both intake and exhaust manifold gaskets?
Yes. Technical references from the Subaru Factory Service Manual and the Subaru parts catalogue list intake manifold gaskets between the manifold and each cylinder head, and exhaust manifold gaskets at the header-to-head flanges (and additional sealing rings at downstream joints). Both the 2.5L FB25 and 3.6L EZ36 engines use them.

What are the tell‑tale signs a manifold gasket is leaking on a 2017 Outback?
For intake leaks: hissing, high or unstable idle, lean fault codes, and poor fuel economy. For exhaust leaks: a ticking noise on cold start, soot marks at the flange, a faint exhaust smell under the bonnet, and slight loss of low‑rpm punch. A smoke test (intake) or listening probe (exhaust) helps confirm it quickly.

Should manifold gaskets be replaced as routine maintenance?
They’re not on a time/kilometre schedule. Replace them whenever the manifold is removed or if leak symptoms appear. During servicing, it’s smart to inspect for staining, soot, loose fasteners, or hardened intake seals and address issues before they escalate.