Citroen C4 Spark Plugs: Intervals, Fitment & Warning Signs
On the C4, a genuinely distinctive cause worth checking for a stubborn misfire: water leaking through the washer seal can short a specific injector.
Illustration for editorial purposes
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A Genuinely Distinctive Cause Worth Checking: Water Ingress Through the Washer Seal
If you're chasing a persistent single-cylinder misfire that hasn't responded to a new coil pack or plugs, this is genuinely worth knowing about: a documented pattern on this platform links water leaking through the windscreen washer reservoir seal to shorting out the nearest fuel injector, causing exactly this kind of stubborn, single-cylinder misfire. A genuinely useful diagnostic clue worth checking directly: if you remove the spark plugs and one specific plug looks noticeably darker or wetter than the others, this points toward that specific cylinder's injector being affected by moisture rather than a generic ignition fault.
If you're testing a coil pack directly, one documented method involves lightly spraying water on the coil while the engine is running and watching for visible arcing, which would confirm a breakdown in the coil's insulation — worth approaching this test with appropriate caution given it involves water near live electrical components.
Citroen C4 Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems
Worn spark plugs on the Citroen C4 rarely announce themselves clearly — a slightly rougher idle, a bit less punch off the line — symptoms easy to blame on almost anything else in the engine bay. The part itself costs very little, which makes it an easy one to overlook for far longer than it should be.
Citroen C4 Spark Plugs: Watch: Replacing It
No C4 III video; shares the 1.2 PureTech EB2 engine
OEM Part Number: confirm via engine code — aftermarket NGK 97434 / Bosch 0 242 129 512
| Petrol engines in this generation | 1.2 PureTech 101 HP (BAHNEA, BAHNKA), 1.2 PureTech 130 HP (BAHNSA, BAHNSB), 1.2 PureTech 155 HP (BAHNNB, BAHNJD); also 1.2 Hybrid 136 HP (BAHPYJ) and 1.2 MHEV 101 HP (BAHPXH) |
|---|---|
| Spark plugs (aftermarket) | NGK 97434 (iridium, M12x1.25, 14 mm hex); NGK 91530 (platinum, M12x1.25, 14 mm); NGK 97999 (iridium, M12x1.25, 16 mm); Champion OE245 (iridium, gap 0.8 mm, 14 mm); Bosch 0 242 129 512 (gap 0.95 mm, M12x1.25, 14 mm); Bosch 0 242 129 510 (gap 0.9 mm, 14 mm); Denso IXEH20TT (iridium, platinum earth, M12x1.25); Beru UPT4 (gap 0.9 mm, M12x1.25, 14 mm) |
| Genuine (OE) numbers quoted | Citroen/Peugeot 9863013680 (iridium, M12x1.25, 14 mm) |
| Fitment notes | Plugs are not tied to individual engine codes. No change interval shown. |
PSA's PureTech turbo engines have a documented history of spark plug problems on earlier production, serious enough that a technical bulletin was issued recommending replacement during routine maintenance regardless of apparent condition. If your C4 is running roughly, misfiring, or hesitating under load, don't assume it's unrelated to the plugs — and always specifically confirm you're buying the turbo-rated plug, not the visually similar non-turbo version.
Citroen C4 Spark Plugs: What They Do
The Citroen C4's spark plugs ignite the compressed fuel-air mixture inside each cylinder, and their condition directly affects combustion efficiency, fuel economy and smooth running. Petrol engines rely entirely on them; diesel engines don't use spark plugs at all, relying on compression instead.
Citroen C4 Spark Plugs: Generations, Engines & Spark Plug Count
| Diesel variants (BlueHDi) | Not applicable — diesel engines use compression ignition and have no spark plugs at all |
|---|---|
| 1.2 PureTech/THP (standard petrol trims) | Genuinely only 3 spark plugs — this engine is shared across the wider PSA/Stellantis range (Peugeot, Citroen, DS), not a four-cylinder |
| GTI/GT (1.6 THP, where fitted) | 4 spark plugs — the performance derivative uses a genuinely different, larger four-cylinder engine from the standard car's 3-cylinder unit |
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Citroen C4 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 Citroen Spark Plugs
The same part, covered across other Citroen models.