Parts for your 2006 Subaru Forester-Spark plugs

2006 Subaru Forester Spark Plugs

Yes, the 2006 Subaru Forester uses spark plugs. The petrol EJ25 boxer engines fitted to the 2006 model (both naturally aspirated and turbo variants) are spark-ignition designs, so spark plugs are essential. This is backed by the Subaru Owner’s Manual and Factory Service Manual for MY2006 Forester, which list spark plug specifications and service intervals, and by the NGK Australia/New Zealand application catalogue that details exact plug types and gaps for these engines. Diesel Foresters didn’t arrive until later overseas markets, so every 2006 Forester runs spark plugs.

On this Forester, spark plugs ignite the air–fuel mix in each cylinder, helping the engine start cleanly, idle smoothly, and deliver decent fuel economy and emissions. Fresh, correctly gapped plugs keep throttle response crisp and reduce misfires, which can otherwise stress the catalytic converter and coil packs.

For servicing, the general rule is: replace at longer intervals on the naturally aspirated 2.5 and a bit sooner on the turbo 2.5XT. Many schedules call for up to about 100,000 km on long-life platinum/iridium plugs for the non-turbo, and around 50,000–60,000 km on the turbo due to higher cylinder pressures and heat. Always check the exact schedule in the vehicle’s maintenance booklet. If it’s doing short trips, running rich, or towing, inspect earlier. Subaru documentation specifies a typical tightening torque of about 25 N·m on aluminium heads, use a torque wrench.

Fit the correct heat range and reach specified for the EJ25. The factory gap is usually pre-set, as a guide, many naturally aspirated plugs are around 1.1 mm, while turbo plugs are commonly 0.7–0.8 mm. Don’t force-adjust fine-wire iridium tips. Subaru and major plug makers advise against anti-seize on modern nickel-plated threads, install dry and to spec. A dab of dielectric grease on the inside of the boots helps future removal and prevents moisture tracking.

Access on the boxer is snug. Working on a cold engine, remove the airbox or battery for room as needed, swap one plug at a time to avoid mixing leads or coils, and replace all four together. Watch for tell-tales of ageing plugs like hard starting, rough idle, higher fuel use, or a flashing check-engine light. Sticking with reputable OE-spec brands from the Subaru schedule keeps the Forester happy on Aussie and Kiwi roads.

• Key tips: cold engine, correct socket and extension, 25 N·m torque, no anti-seize, verify gap, replace boots if cracked.

Popular questions about 2006 Subaru Forester spark plugs

What spark plugs does a 2006 Forester use?
The 2006 Forester typically runs long-life platinum or iridium plugs matched to the specific engine variant. The naturally aspirated EJ253 commonly specifies a long-life plug with a 1.1 mm gap, while the turbo EJ255 calls for an iridium fine-wire plug with a tighter 0.7–0.8 mm gap. Always confirm by VIN against the Subaru schedule or a trusted parts catalogue for the exact part number and heat range.

How often should the plugs be replaced?
For many 2006 Foresters, the naturally aspirated 2.5 is serviced around the 100,000 km mark on long-life plugs, whereas the 2.5XT turbo is typically due nearer 50,000–60,000 km. If the vehicle sees lots of cold starts, short trips, or heavy loads, consider inspecting earlier. Follow the maintenance booklet for the definitive interval.

Can a competent DIYer change them at home?
Yes, with patience and the right tools. Work with the engine cold, remove intake ducting or the battery to gain space, use a quality spark plug socket, set or verify the gap, and torque to about 25 N·m. Don’t use anti-seize on modern plated threads. Swap one lead or coil at a time to keep firing order correct, and finish with a quick check for smooth idle.