Peugeot 108 Spark Plugs: Intervals, Fitment & Warning Signs

If your 108 has the PureTech engine, a genuine, real phenomenon explains knocking under load — plus real, documented confusion over the correct plug part number.

Illustration for editorial purposes

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Peugeot 108 Spark Plugs: OEM Part Number

Accuracy note: we weren't able to verify a confident Peugeot 108 spark plugs part number at the time of writing. Please confirm the correct part via a Peugeot dealer or parts specialist using your VIN.

A Genuine, Real Phenomenon Worth Understanding: LSPI on Turbo PureTech Engines — Peugeot 108 Spark Plugs

If your car has a PureTech turbocharged petrol engine and you're experiencing a knocking or misfiring sensation specifically under load at low engine speed, it's worth knowing about Low Speed Pre-Ignition (LSPI) — a genuine, industry-recognised phenomenon affecting small, turbocharged direct-injection engines generally, not something unique to Peugeot. It occurs when the fuel-air mixture ignites prematurely, before the spark plug fires, causing a knock that can potentially damage the engine over time if it happens repeatedly. Genuinely useful to know: LSPI is understood to be exacerbated by certain oil additive packages, and switching to an oil that meets the correct, current specification for this engine — combined with using a higher-octane fuel, which some owners report noticeably reduces the frequency of the knock — are the cheapest, simplest first steps worth trying.

A genuinely confusing, real fitment detail worth checking carefully: there's documented confusion among both parts suppliers and owners about the correct spark plug for this engine — some sources list the ZR5 heat range as the current Bosch-recommended part, while many retailers still show the ZR6 as standard, with owners speculating Bosch may have revised their recommendation at some point without this being consistently reflected across every parts catalogue. Given how sensitive these small turbo engines can be to using the wrong heat-range plug, it's genuinely worth cross-checking your specific engine code against your VIN via a specialist parts lookup rather than assuming the first result from a generic search is correct.

Peugeot 108 Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems

A worn set of spark plugs in the Peugeot 108 doesn't make itself obvious: idle roughens slightly, acceleration loses a bit of urgency, and both symptoms are easy to blame on something else entirely. Given how inexpensive the part is, it often gets neglected for far longer than it should.

Before you buy: plug type and gap specification vary by engine size and generation. Always confirm against your VIN before ordering.

Peugeot 108 Spark Plugs: What They Do

Every combustion cycle in the Peugeot 108's petrol engine starts with a spark plug igniting the compressed fuel-air mixture, and their condition shapes efficiency, economy and smoothness directly. Diesel versions don't need them at all, relying purely on compression to ignite fuel.

Peugeot 108 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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Peugeot 108 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 Peugeot Spark Plugs

The same part, covered across other Peugeot models.