Parts for your 2013 Subaru Impreza-Spark plugs

2013 Subaru Impreza spark plugs — what they do and when to replace them

Yes — the 2013 Subaru Impreza uses spark plugs. Technical sources including the Subaru Owner’s Manual maintenance schedule for the 2013 Impreza, the Subaru Factory Service Manual (FB20 engine), and OEM application catalogues from NGK and Denso all specify four spark plugs (one per cylinder) for the 2.0‑litre FB20 petrol boxer engine.

In this car, spark plugs ignite the air–fuel mix in each cylinder, kicking off combustion so the engine fires cleanly, pulls strongly, and keeps fuel use and emissions in check. Good plugs help cold starts on frosty mornings, smooth out idle, and keep the Impreza feeling lively on the open road.

As part of routine servicing, plugs are a small part with a big job. The 2013 Impreza is typically fitted with long‑life iridium plugs. Subaru’s schedule for this model calls for replacement around the 60,000 mile/96,000 km mark in many markets, AU/NZ guidance for iridium plugs commonly lands around 100,000–120,000 km, depending on conditions. Stop–start city driving, frequent short trips, or dusty rural roads can shorten that interval. A technician will also check for misfires and adjust plans accordingly.

Owners and workshops should stick with the correct spec plug (OEM‑equivalent iridium), the right heat range, and the factory gap and torque. Most iridium plugs are pre‑gapped around 1.1 mm, don’t force the gap on fine‑wire designs. Fit them to a cold engine, use a torque wrench to the factory spec from the Subaru service manual, and avoid anti‑seize unless the plug maker explicitly allows it — modern plated threads don’t need it and over‑tightening can crack the head. While in there, it’s smart to inspect coil‑on‑plug boots, look for oil in the plug tubes, and clear any debris before removal.

• Tell‑tales it’s time: rough idle, sluggish accel, higher fuel use, harder starts, or a check engine light with misfire codes (P0301–P0304).
• Access on the boxer can be snug, removing the intake snorkel makes life easier on some sides.
• Keep records — noting the brand, part number, and odometer helps plan the next change.

Look after the plugs and the 2013 Impreza stays perky, frugal, and happy to tackle the daily commute or a weekend fang down the coast.

How often should 2013 Subaru Impreza spark plugs be replaced?

Expect roughly 96,000–100,000 km for factory iridium plugs, with earlier changes if the car does lots of short trips, idles heaps, or drives dusty roads. If there’s any hint of misfire or poor economy, a check and earlier replacement is worthwhile.

What spark plug type and gap does the 2013 Impreza use?

Use OEM‑equivalent iridium plugs specified for the FB20 engine. They’re usually pre‑gapped around 1.1 mm. Don’t force the gap on fine‑wire iridium, confirm specs under the bonnet sticker or in the Subaru manual and install to factory torque.

What are the symptoms of worn spark plugs on a 2013 Impreza?

Common signs are rough idle, hesitation, harder starting, higher fuel use, and a check engine light for cylinder misfire. If those crop up, a plug and coil inspection should be next on the list.