Subaru Outback Spark Plugs: Intervals, Fitment & Warning Signs
A genuinely useful diagnostic technique: misting water over a suspected coil helps confirm it as the cause of a misfire — plus a warning that coils aren't interchangeable between vehicles, and using the wrong one can damage the ECU.
Illustration for editorial purposes
Opens live listings in a new tab.
OEM Part Number: confirm via engine code — aftermarket NGK 6283 / Bosch 0 242 135 553
| Petrol engines in this generation | See the fitment notes |
|---|---|
| Spark plugs (aftermarket) | NGK stock no. 1654 (iridium, M12x1.25, 14 mm hex); NGK 6283 (iridium, M12x1.25, 14 mm hex); NGK 93482 (iridium, M12x1.25, 14 mm hex); NGK 7505 (iridium, M14x1.25, 16 mm hex); NGK 2477 (iridium, M14x1.25, 16 mm hex); Bosch 0 242 135 553 (1.0 mm gap, M12x1.25, 14 mm hex); Bosch 0 242 129 529 (1.1 mm gap, M12x1.25, 14 mm hex); Bosch 0 242 236 593 (1.1 mm gap, M14x1.25, 16 mm hex) |
| Genuine (OE) numbers quoted | 22401-EA016 (Denso FXE22HR11); 9091901253 (Kamoka 7100053); 22401AA750 (Kamoka 7100052) |
| Fitment notes | The 2.5 flat-four engines use the M12x1.25 14 mm hex iridium plugs; the M14x1.25 16 mm hex plugs (NGK 7505, Champion CCH9033, Bosch 0 242 236 593) are listed for the other engines such as the 3.6, so check the engine code. Brisk 1708 and 1621 quote a 100,000 km interval. Beru is not listed. |
Subaru Outback Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems
On the Subaru Outback, symptoms of worn spark plugs are subtle by nature — a touch rougher at idle, a little less responsive off the line — and easy to attribute to almost any other engine gremlin. Because the part itself is so cheap, it's routinely overlooked well past when it should've been changed.
Subaru Outback Spark Plugs: What They Do
How well the Subaru Outback's engine runs, how efficiently it burns fuel, and how smooth it feels are all tied to spark plug condition, since these ignite the compressed fuel-air mixture in each cylinder. That's a petrol-engine job specifically — diesels ignite fuel through compression and have no spark plugs at all.
Subaru Outback Spark Plugs: Generations & Spark Plug Count
| Diesel variants, where fitted | Not applicable — diesel engines use compression ignition and have no spark plugs at all |
|---|---|
| Petrol variants (all trims, including WRX/STI) | 4 spark plugs — Subaru's distinctive flat-four "boxer" layout is still a four-cylinder engine for plug-count purposes, just with the cylinders arranged horizontally in opposing pairs rather than in a line or a V |
Subaru Outback Spark Plugs: Watch: Replacing It
Outback BS
Opens live listings in a new tab.
A Genuinely Useful, Real Diagnostic Technique Worth Trying — Subaru Outback Spark Plugs
If you suspect a specific ignition coil is causing a misfire, this is genuinely worth trying: lightly misting water over the suspected coil with the engine running and watching whether it immediately stumbles or misfires is a genuinely practical way to confirm the coil as the cause. This works because water finding its way into a coil with a cracked casing or compromised connection can cause the spark to short and jump to the rocker cover instead of reaching the cylinder properly — a distinctive, testable symptom worth trying before committing to a full coil replacement based on guesswork alone.
It's also genuinely worth knowing an honest warning about parts sourcing: numerous documented reports describe counterfeit NGK spark plugs being sold through online stores, worth bearing in mind if a genuine-brand plug replacement doesn't resolve a misfire as expected. It's also worth knowing that a coil pack's epoxy resin developing visible cracks is a specific, real cause of misfires worth checking for directly — one owner replaced three of six coils on the same engine over time, with cracked epoxy confirmed as the cause on each occasion.
Subaru Outback Spark Plugs: Warning Signs, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Spark Plugs Guide for symptoms of worn plugs, why matching your exact plug specification matters, and trusted brands to buy from.
More Subaru Spark Plugs
The same part, covered across other Subaru models.