BMW X3 Cabin Air Filter: Intervals, Fitment & Warning Signs

On the X3, recirculation mode has genuinely been documented causing a musty smell within a specific temperature range on related models.

Generation covered: this guide is for the third-generation X3 (G01, 2018–present), with particular focus on 2018–2023 registered examples now old enough for parts to be a common search. Check your logbook or VIN if you're unsure which generation you have.

Illustration for editorial purposes

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OEM Part Number: confirm via VIN — cabin air filter (aftermarket) Filtron K1425 / Denso DCF600P

Accuracy note: Covers the BMW X3 (G01 2018-) as listed in the UK aftermarket catalogues. A cabin filter is a cheap part, but it is bought by number, and the number depends on whether your car was built with a standard particulate filter or an activated-carbon one, as well as on trim and build date. The references below are aftermarket catalogue listings for this generation, grouped by brand; the carmaker's own number is not quoted in those listings, so check the genuine filter against your VIN if you want a guaranteed match. Carbon versions carry their own numbers and are listed separately.

Cabin filter, standard (aftermarket)	Filtron K1425, Denso DCF600P
Activated-carbon version (aftermarket)	Filtron K 1425A, Febi 104810, Valeo 715836
Genuine (OE) number	Not quoted in the catalogue listings — the fitted filter varies by trim and build date, so order the genuine one against your VIN
Fitment notes	Standard and carbon filters have different numbers, and the right size depends on trim and build date. Check which type your car was built with before ordering.

BMW X3 Cabin Air Filter: Easy to Forget, Easy to Fix

There's no performance downside to a neglected BMW X3 cabin filter, which is precisely the problem: nothing about how the car drives will tell you it needs changing, so it often gets forgotten until a musty smell or weak airflow forces the issue.

Before you buy: filter size and whether your car uses a standard or activated-carbon filter varies by trim. Always confirm against your VIN before ordering.

BMW X3 Cabin Air Filter: What It Does

Don't confuse this with the BMW X3's engine air filter — they're unrelated parts. The cabin filter's job is cleaning air before it reaches the ventilation system, catching dust and pollen, with activated-carbon versions also filtering some airborne odours.

BMW X3 Cabin Air Filter: Watch: Replacing It

🎬 Watch: BMW X3 Cabin Air Filter Replacement DIY (2018-2025 BMW G01 X3, G02 X4)

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A Genuinely Useful Piece of Context Worth Knowing About Musty Smells — BMW X3 Cabin Air Filter

If a musty smell only appears sometimes rather than constantly, this is genuinely worth knowing: running the system on recirculation mode has been documented causing a musty smell specifically within a certain temperature range on related BMW models, while switching to fresh air mode instead avoided the smell entirely.

A genuinely useful preventative tip worth knowing: switching the air conditioning off, while leaving just the fan running, for a couple of minutes before parking helps dry out the evaporator, genuinely helping prevent mould and mildew developing there.

It's also genuinely worth knowing that there isn't a separate "AC filter" distinct from the cabin air filter — they're the same single part, and it needs to be properly replaced rather than simply cleaned if it's genuinely causing a smell.

BMW X3 Cabin Air Filter: Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Cabin Air Filter Guide for signs it needs changing, confirming fitment against your VIN, and choosing standard, carbon, or HEPA media.

More BMW Cabin Air Filter

The same part, covered across other BMW models.