Parts for your 2008 Subaru Forester-Manifold gasket

2008 Subaru Forester manifold gasket — what it does and when to replace it

Per the Subaru Factory Service Manual for the 2008 Forester (EJ25 2.5‑litre, including XT), the engine uses manifold gaskets at the intake manifold-to-cylinder head and exhaust manifold-to-cylinder head joints. Subaru’s own service literature and major gasket catalogues for EJ25 applications specify multi‑layer steel (MLS) or equivalent composite manifold gaskets, so a manifold gasket absolutely is fitted and relevant on this model.

On this Forester, the manifold gaskets seal high‑vacuum intake runners and high‑temperature exhaust ports. Their job is simple but critical: keep unmetered air out of the intake, keep exhaust gases in the headers, prevent loss of performance, and stop heat, soot, and noise from escaping. Proper sealing also protects nearby components (like plastic loom clips and O2 sensor wiring) from hot gas leaks.

Owners will usually notice a crook manifold gasket through one or more of these signs:

• Ticking or chuffing noise on cold start that gets quieter as it warms (often exhaust leak)
• Rough idle, lean codes, or high fuel trims (intake leak)
• Soot trails around the exhaust flange or a whiff of fumes in the bay
• Lower power, poor fuel economy, or a whistle under load

Servicing advice for the 2008 Forester’s manifold gaskets is straightforward. They’re not a scheduled replacement item, but any time the intake manifold or exhaust manifold is removed—say for spark plugs on the turbo, valve cover work, or header swaps—fresh gaskets should be fitted. The Subaru FSM calls for proper bolt/nut torque and sequence, following that procedure is key to avoid uneven clamping and future leaks. Reusing crushed gaskets is false economy, especially on the exhaust side where heat cycles are brutal.

Quality matters. Go for OEM‑spec MLS or reputable aftermarket equivalents designed for the EJ25. Clean both mating faces until they’re spotless and flat, seat the gasket dry (no sealant unless the manufacturer explicitly says so), and torque in stages using the factory pattern. If the vehicle is an XT, remember there are additional sealing joints (up‑pipe/down‑pipe) that should be checked while you’re there.

If a leak’s suspected, a quick smoke test (intake) or soapy‑water test on a cold start (exhaust) helps confirm it. Catching a small leak early can save O2 sensors, catalytic converters, and keep the Forester running sweet as.

Popular questions about 2008 Subaru Forester manifold gaskets

Do all 2008 Foresters use the same manifold gasket?
Both naturally aspirated and XT turbo 2008 Foresters use intake and exhaust manifold gaskets at the head. The gasket shapes match the EJ25 port layout, though turbo models have extra gaskets elsewhere in the system. Always match gaskets to VIN/engine code to ensure correct port shape and bolt pattern.

Can a manifold leak damage the engine?
An intake leak can drive lean operation, rough running, and catalyst stress, an exhaust leak can raise O2 sensor noise, skew fuel trims, and overheat nearby parts. Long term, that can cost more than simply replacing the gaskets and torquing things to spec.

Should sealant be used with the manifold gaskets?
For OEM‑style MLS intake and exhaust manifold gaskets on the EJ25, no additional sealant is typically specified by Subaru. Clean, flat faces and correct torque are the go. Only use sealant if the gasket manufacturer’s instructions call for it.