Parts for your 2007 Subaru Impreza-Fuel cap

2007 Subaru Impreza Fuel Cap — Purpose, care, and when to replace

For the 2007 Subaru Impreza, a fuel cap is absolutely fitted and relevant. Technical sources — the 2007 Subaru Impreza Owner’s Manual (Fuel filler lid and cap), Subaru service literature on the evaporative emission control (EVAP) system, and standard OBD‑II diagnostic guidance — specify a screw‑on, tethered petrol cap that must be tightened until it clicks. This cap is part of the sealed EVAP system used to control fuel vapours and maintain correct tank pressure.

On this Impreza, the fuel cap’s job is simple but crucial. It seals the filler neck to stop petrol fumes escaping, keeps water and grit out of the tank, and helps the EVAP system hold the slight vacuum or pressure it needs. If the cap is loose, wrong, or its seal is perished, the car can throw EVAP‑related fault codes (often P0440, P0455 or P0456) and light the check engine lamp. It can also lead to fuel smells around the rear guard and unnecessary evaporation of fuel, which is no good for economy or emissions.

As part of routine servicing, the cap deserves a quick once‑over. Owners should confirm the ratchet clicks when tightened, inspect the rubber seal for cracks or flattening, and make sure the tether isn’t broken. A clean, slightly damp cloth will remove dust from the seal and filler neck, avoid petroleum grease, though a tiny smear of silicone dielectric grease can keep the seal supple in hot Aussie and Kiwi conditions.

• Signs it’s due for replacement:
  • Persistent fuel smell after driving or parking
  • Cracked, hardened, or flattened rubber gasket
  • Cap won’t “click” or the ratchet slips
  • Recurring EVAP codes after hoses and lines check out

When replacing, a genuine Subaru or high‑quality EVAP‑rated cap is the smart pick, universal caps can look right but vent incorrectly. Fitment is straightforward: remove the old cap, wipe the filler neck, then install and turn until it clicks several times. If a cap issue triggered a fault light, the code can be cleared with a scan tool or will generally clear itself after several drive cycles once the system passes its self‑tests. Given age and climate, many owners replace the cap proactively every 5–10 years, or sooner if symptoms show.

Popular questions

What type of fuel cap does a 2007 Subaru Impreza use?
It uses a screw‑on, tethered cap designed for a sealed EVAP system. The correct cap will “click” when tightened and has a moulded rubber gasket that maintains vapour sealing. A genuine Subaru part or an EVAP‑rated equivalent ensures proper venting and compliance.

Why does the check engine light come on after refuelling?
A loose or faulty fuel cap is a common cause. If the cap isn’t clicked tight, or the seal is perished, the EVAP system detects a leak and may log codes such as P0440, P0455, or P0456. Tighten the cap until it clicks and drive a few trips, if the light stays on, have the system smoke‑tested.

How often should the fuel cap be replaced?
There’s no strict kilometre interval, but with age and heat, seals harden. Inspect at every service, many Impreza owners find replacement between 5–10 years keeps EVAP faults and fuel smells at bay. Replace immediately if the cap won’t click or the gasket shows cracking.