Parts for your 2017 Subaru Legacy-Exhaust gasket

2017 Subaru Legacy exhaust gasket — what it does and when to replace it

Yes, the 2017 Subaru Legacy uses multiple exhaust gaskets. This is confirmed by Subaru’s service manual for the 2015–2019 Legacy platform (BN/BS) under the Exhaust section, the Subaru Technical Information System (STIS), and the Subaru Genuine Parts catalogue for MY2017. Both the 2.5i (FB25) and 3.6R (EZ36) variants are built with exhaust manifold-to-head gaskets, crush “donut” gaskets at the front pipe joints, and flat flange gaskets further down the system. They’re there by design to seal hot exhaust gases and keep the system leak-free.

On this Legacy, exhaust gaskets do a few big jobs. They seal the manifold to the cylinder head, contain pressure and heat where the front pipe meets the catalytic converter assembly, and keep each flange join tidy so there’s no hissing, ticking, or fumes sneaking out. Good sealing also helps the oxygen sensors read cleanly, which keeps fuel trims and emissions in check. Subaru typically uses multi-layer steel (MLS) manifold gaskets and graphite/metal donut gaskets that crush slightly for a reliable seal through repeated heat cycles.

There isn’t a scheduled replacement interval for exhaust gaskets