Parts for your 2008 Subaru Impreza-Manifold gasket

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

Yes, a manifold gasket is absolutely used on the 2008 Subaru Impreza. Referencing technical sources such as the Subaru Factory Service Manual for the 2008MY Impreza (Engine section), the Subaru Technical Information System (STIS), and the Subaru FAST electronic parts catalogue, this model is shown to have replaceable intake manifold gaskets (between the intake manifold and cylinder heads) and exhaust manifold gaskets (between the exhaust manifold/header and heads). Turbo variants (WRX/STI) also use additional up‑pipe and turbo outlet (downpipe) gaskets. So the part is relevant to every 2008 Impreza engine family, from the naturally aspirated EJ to the turbocharged EJ variants.

On this car, the manifold gasket’s job is to keep things sealed where it matters most. The intake manifold gaskets stop unmetered air sneaking into the engine, keeping idle smooth, fuel trims tidy, and cold starts drama‑free. The exhaust manifold gaskets keep hot gases inside the headers so there’s no ticking under the bonnet, no sooty leaks, and no whiffs of exhaust in the cabin. On turbo cars, good sealing also helps the turbo spool cleanly and keeps boost where it should be.

They’re not a routine “every X kilometres” service item, but they are a must‑replace whenever the manifold is removed, or when symptoms suggest a leak. Tell‑tale signs include:

• Hissing, surging idle, or lean fuel trim codes (intake side)
• Ticking on cold start, exhaust smell, or sooty marks at the flange (exhaust side)
• Poor fuel economy or a sluggish feel, especially on turbo models

When replacing, stick with quality gaskets (OE‑style multi‑layer steel for exhaust is ideal). Clean both mating faces until spotless, avoid scraping grooves into the alloy, and do not smear sealant on modern gaskets unless Subaru explicitly specifies it. Fit new fasteners if they’re corroded, tighten in the proper sequence, and torque to spec with a calibrated wrench. After a few heat cycles, a quick check for any weeps, ticks, or vacuum leaks is smart practice.

As part of regular servicing, a visual once‑over goes a long way: look for staining, soot tracks, loose hardware, or perished vacuum hoses at the intake. If a manifold is coming off for other work (plugs on some models, injector service, or header removal), budget fresh gaskets—cheap insurance for a rock‑solid seal and happy motoring around Aus or Aotearoa.

• Does a 2008 Subaru Impreza have manifold gaskets?
  Yes. Subaru’s 2008 Factory Service Manual and parts catalogue list intake manifold gaskets and exhaust manifold gaskets across the range, with extra turbo‑related gaskets on WRX/STI models.
• What are the signs a manifold gasket is failing on a 2008 Impreza?
  For intake: hissing, rough idle, lean codes, and poor economy. For exhaust: a ticking noise on cold start, exhaust odour, and dark sooty marks at the flange.
• Should sealant be used when installing these gaskets?
  Generally no. Modern Subaru intake and exhaust manifold gaskets are designed to seal dry. Only use sealant where Subaru service information specifically calls for it.