Parts for your 2023 Subaru Impreza-Head gasket

2023 Subaru Impreza head-gasket — what it does, why it matters, and when to sort it

Referencing technical sources including the Subaru Service Manual (STIS) for the FB-series 2.0‑litre boxer engine used in the MY23 Impreza (Cylinder Head section) and Subaru’s genuine parts catalogue for MY23 Impreza (engine/cylinder head group), a head-gasket is absolutely fitted and relevant on this vehicle. These documents describe the multi‑layer steel (MLS) head gaskets installed between each cylinder head and the aluminium block.

On the 2023 Subaru Impreza, the head-gasket seals combustion pressure, coolant and oil galleries where the FB20’s two cylinder heads meet the block. Because it’s a horizontally opposed (boxer) engine, precise sealing is crucial to keep compression up, keep oil where it belongs, and let coolant do its job without cross‑contamination. The MLS design used on modern FB engines is far more robust than the older EJ-era gaskets, helping reliability for everyday Kiwi and Aussie driving.

While a head-gasket isn’t a routine “service item”, good servicing helps it live a long, drama‑free life. Overheating is the enemy, so the cooling system needs to stay healthy and bled correctly.

• Watch for tell‑tales: unexplained coolant loss, overheating under load, heater going cold, milky oil, sweet exhaust smell, persistent bubbles in the overflow, or a rough cold start.
• Stick to the coolant specified in the owner’s manual and maintain the correct mix. Don’t top up with plain water unless it’s an emergency.
• Keep the radiator cap, thermostat, fans, and hoses in good nick