Citroen C1 Spark Plugs: Intervals, Fitment & Warning Signs
On the C1, 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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OEM Part Number: confirm via engine code — aftermarket NGK 97999 / Bosch 0 242 129 525
| Petrol engines in this generation | 1.0 VTi 69 HP, 1.0 VTi 72 HP, 1.2 VTi 82 HP (no engine codes) |
|---|---|
| Spark plugs (aftermarket) | NGK 97999 (iridium, 5 kOhm suppression, M12x1.25, 16 mm hex); NGK 5989 (iridium, 5 kOhm suppression, M12x1.25, 14 mm hex); Denso VXUH22I (iridium centre, platinum earth, resistor, M12x1.25); Denso FC16HR-Q8 (iridium centre, platinum earth); Bosch 0 242 129 525 (gap 0.9 mm, M12x1.25, 16 mm hex, 23 Nm); Bosch 0 242 129 529 (gap 1.1 mm, 14 mm hex, 23 Nm); Champion CCH9412 (iridium, gap 1.0 mm, 14 mm hex); Champion OE261 (iridium, gap 0.7 mm, 14 mm hex) |
| Genuine (OE) numbers quoted | Citroen/Peugeot 1611548180 and 1654509380; Denso VXUH22I = A0041592503; Denso FC16HR-Q8 = 90919-01289; Denso IXUH22I = 90048-51189-000; Renault 224015145R and 224019133R |
| Fitment notes | Plugs are not tied to individual engines. Two families exist, 16 mm hex and 14 mm hex, both M12x1.25, and most listed plugs are iridium. No change interval shown. The listed model years run 2014 to 2016. |
A Genuinely Distinctive Cause Worth Checking: Water Ingress Through the Washer Seal — Citroen C1 Spark Plugs
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 C1 Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems
On the Citroen C1, there's rarely a clear signal when spark plugs wear out — just a rougher idle, marginally less pep off the line — vague enough to get pinned on other engine issues. Since the part costs so little, it's also one of the easiest things to keep putting off.
Citroen C1 Spark Plugs: Watch: Replacing It
Generation not confirmed from title; C1/107/Aygo version is https://www.youtube.com/watch?v=yQqbFBizuMw
Citroen C1 Spark Plugs: What They Do
On the Citroen C1, combustion efficiency, fuel economy and smooth running all trace back to spark plug condition, since these are what ignite the compressed fuel-air mixture in each cylinder. Petrol engines depend on them entirely — diesels skip spark plugs altogether, igniting fuel through compression instead.
Citroen C1 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 C1 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.