BMW 4 Series Spark Plugs: Intervals, Fitment & Warning Signs

On the 4 Series, related engines have genuinely had a confirmed bulletin addressing a fault where the engine fails to restart after a cold start.

Illustration for editorial purposes

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BMW 4 Series Spark Plugs: OEM Part Number

Accuracy note: we weren't able to verify a confident BMW 4 Series spark plugs part number at the time of writing. Please confirm the correct part via a BMW dealer or parts specialist using your VIN.

BMW 4 Series Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems

A worn set of spark plugs in the BMW 4 Series 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.

BMW 4 Series Spark Plugs: What They Do

Every combustion cycle in the BMW 4 Series'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.

BMW 4 Series Spark Plugs: Generations, Engines & Spark Plug Count

Diesel variants	Not applicable — diesel engines use compression ignition and have no spark plugs at all
Petrol four-cylinder (most trims)	4 spark plugs — one per cylinder
Petrol six-cylinder (M-Performance trims, where fitted)	6 spark plugs — a genuinely different engine family (BMW's inline-six) from the standard four-cylinder units, not a bored-out version of the same engine

BMW 4 Series Spark Plugs reference plate

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A Genuinely Useful Piece of Context Worth Knowing About Misfires — BMW 4 Series Spark Plugs

If the engine has turned over but failed to actually start on a repeated cold-start attempt, this is genuinely worth knowing: related BMW engines have had a confirmed technical bulletin addressing exactly this fault, caused by unfavourable software combined with the original spark plug part, since superseded twice with revised versions.

A genuinely useful diagnostic technique worth trying: swapping a suspect coil to a different cylinder is a direct way to confirm whether a misfire is genuinely coil-related — if the misfire follows the coil, this confirms it; if it stays on the original cylinder, the cause is more likely the plug itself.

It's also genuinely worth knowing that coil packs have been documented failing even on cars with genuinely low mileage.

BMW 4 Series 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 BMW Spark Plugs

The same part, covered across other BMW models.