Parts for your 2015 Subaru Forester-Exhaust gasket

2015 Subaru Forester exhaust gasket: what it does and how to look after it

Yes, the 2015 Subaru Forester uses exhaust gaskets. The Subaru Factory Service Manual (FSM) for the SJ-series Forester specifies multiple exhaust gaskets and crush rings at the manifold-to-cylinder head, front pipe/donut joint, intermediate and rear flange joints, and—on 2.0XT turbo models—the turbo-to-downpipe interface. The Subaru electronic parts catalogue (FAST) lists these gaskets as service parts and the FSM instructs technicians to renew them whenever disturbed. Those technical sources make it clear the exhaust gasket is absolutely relevant to this model.

On a 2015 Forester, exhaust gaskets seal the hot gas path so the engine breathes properly and emissions systems work as intended. They’re typically multi‑layer steel (MLS) at the manifold-to-head, a metal/graphite “donut” ring at the front pipe, and flat ring gaskets at the flanges further rear. Turbo variants add a high‑temperature metal gasket at the turbo outlet. When they lose tension from heat cycling, or the hardware corrodes, small leaks start—often before any obvious hole appears in the pipework.

Signs a Forester’s exhaust gasket is on the way out include:

• A ticking sound on cold start that softens as it warms
• Exhaust odour in the engine bay or under the floor
• Sooty marks around a flange or at the manifold-to-head
• Slight loss of pep, rough idle, or a fuel trim fault if the leak is upstream of the O2 sensor

Service advice for owners and workshops:

• Replace any exhaust gasket that’s been disturbed. The FSM calls for renewal rather than re‑use, as crush-style gaskets don’t reliably reseal.
• Use quality OEM‑equivalent gaskets, MLS for the manifold and the correct-size donut for the front pipe. Turbo models need the correct high‑temp turbo outlet gasket.
• Inspect studs, springs and flange bolts. Replace corroded hardware and tighten to the FSM torque specs to avoid warping flanges or pinching O2 sensor bungs.
• At each service, give the joints a quick look for soot trails and listen for a cold-start tick—early fixes are cheaper than dealing with seized fasteners later.
• If there’s a persistent leak, have a smoke or pressure test done, it’s quick and pinpoints the exact joint.

Look after the gaskets and hardware and the 2015 Subaru Forester’s exhaust will stay quiet, safe, and compliant—no droning, no fumes, just smooth running for many kilometres.

Popular questions about 2015 Subaru Forester exhaust gaskets

How can someone tell which exhaust gasket is leaking on a 2015 Subaru Forester?
Start from a cold engine and listen for a sharp tick near the manifold and front pipe. Lightly feel (without touching hot parts) for puffs at joints, look for black soot at flanges, and check the manifold-to-head area. A workshop can run a smoke or low‑pressure test to pinpoint the exact joint, including the turbo outlet on XT models.

Do exhaust gaskets need replacing every time the exhaust is removed?
Yes—on this model, crush and MLS gaskets are considered single‑use. The Subaru FSM directs renewing them whenever they’re disturbed to ensure a reliable seal. Reusing old gaskets often leads to early leaks and seized hardware down the track.

Should sealant be used on a Forester’s exhaust gaskets?
No sealant is normally required or recommended. Use the correct Subaru‑spec gasket and tighten hardware to the FSM torque values. If there’s pitting or flange distortion, address that rather than relying on paste—it’s a short‑term fix at best.