Parts for your 2008 Subaru Forester-Ignition leads

2008 Subaru Forester ignition leads: what’s fitted and how to look after them

Based on technical references such as the Subaru Factory Service Manual (SG/SH 2008, Ignition section), the Subaru parts catalogue, and NGK’s AU/NZ application data, ignition leads are fitted to 2008 Forester non‑turbo models (EJ253 SOHC). These use a remote coil pack and four high‑tension leads to the spark plugs. The 2008 Forester XT turbo (EJ255 DOHC), however, uses coil‑on‑plug direct ignition with individual coils on each plug and therefore has no traditional ignition leads.

Why the difference? Subaru moved the turbo models to direct ignition for tighter control of spark timing and improved reliability under boost. The FSM for the EJ255 shows individual coil modules and no HT leads, while NGK’s catalogue lists lead sets for the 2.5 non‑turbo but none for the 2.5 turbo, confirming the split across the range.

For owners of a 2008 Forester 2.5 non‑turbo, the ignition leads play a simple but critical role: they carry high voltage from the coil pack to each spark plug with minimal loss. Good leads mean easy cold starts, smooth idle, solid fuel economy, and fewer misfires. Over time, heat, oil vapour, and vibration can cause the insulation to harden or crack, and internal resistance to climb, which shows up as hesitation under load, rough running in the wet, or tell‑tale arcing marks under the bonnet.

As part of routine servicing, it’s smart to inspect the leads every 20,000–30,000 km and consider replacement around 100,000 km or earlier if symptoms appear. Look for perishing at the boots, green corrosion on terminals, and any white tracking on the lead jackets. When replacing, do one lead at a time to maintain firing order, push the boots on until a positive “click” is felt, and route them in the factory clips away from hot exhaust bits. Pairing new leads with fresh spark plugs (correct NGK/NGK equivalents, gapped to spec) maximises the result.

If the vehicle is a 2008 Forester XT turbo, there are no traditional ignition leads to service. Instead, check the coil‑on‑plug units for cracked housings, oil in the plug tubes, and secure electrical connectors, and replace individual coils as needed.

• Relevant technical sources: Subaru Factory Service Manual (2008 SG/SH Ignition), Subaru Parts Catalogue (EJ253 lead set listings), NGK AU/NZ application catalogue for 2008 Forester.

Popular questions about 2008 Subaru Forester ignition leads

Does my 2008 Forester have ignition leads?
Non‑turbo 2.5 (EJ253) models do have ignition leads between a central coil pack and the spark plugs. The turbo XT (EJ255) uses coil‑on‑plug and doesn’t have traditional leads. If unsure, a quick look under the bonnet will show four thick leads coming off a coil pack on the non‑turbo.

How often should the ignition leads be replaced?
There’s no hard expiry, but many workshops in Australia and New Zealand recommend inspecting at each major service and replacing around 100,000 km, or sooner if there are misfires, rough idle, or visible damage. Coastal or high‑heat use can shorten their life.

What are the symptoms of worn ignition leads?
Common signs include a stumble under load, poor fuel economy, hard starting when cold or wet, and visible arcing or cracking on the leads. A dark‑garage mist test (light spray of water with the engine idling) can reveal arcing on tired leads—avoid touching anything while running.