Fault File
All models / All cars / Saloons & estates / BMW 3 Series

BMW 3 Series

All generations and engines together · 354,823 MOT tests in the 2025 data · typical mileage at age 7: 74k

First-time failure at age 7
15.0%
Across 28,026 tests. The average across all tracked models is 19.5%.
Rank at age 7
54 of 239
1 = lowest failure rate among the models tracked.
Typical mileage at age 7
74k miles
Check the mileage view below; low-mileage models can look better by age than they are.

Generation

Split by first-registration year. Cars registered in a changeover year can belong to either generation.

How this model wears

BMW 3 SeriesClass average, all tracked models

Known issues

Measured

Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.

What testers flag

Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.

Faults with the car itself

The rows that judge the model rather than its keeper. 115,442 tests in this band.

A shock absorber damaged to the extent that it does not function or showing signs of severe leakage
Advisory
5.5%class 2.3%
A suspension pin, bush or joint excessively worn
Advisory
5.3%class 5.9%
Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users
Advisory
3.0%class 2.4%
A shock absorber damaged to the extent that it does not function or showing signs of severe leakage
Fail
1.6%class 0.4%
Play in steering rack inner joint(s)
Advisory
1.4%class 1.1%
Excessive fluctuation in brake effort through each wheel revolution.
Advisory
0.8%class 0.6%
A wheel badly distorted or wear between wheel and hub at spigot mounting
Advisory
0.7%class 0.6%
A wheel with a loose or missing wheel nut, bolt or stud
Fail
0.7%class 0.2%
A suspension pin, bush or joint excessively worn
Fail
0.6%class 0.9%

Wear, upkeep and luck

Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.

Tyre tread depth not in accordance with the requirements
Advisory
30.1%class 22.9%
A brake lining or pad worn below 1.5mm
Advisory
10.1%class 8.7%
Brake disc or drum excessively weakened, insecure or fractured
Advisory
8.4%class 10.1%
A tyre seriously damaged
Advisory
6.7%class 13.4%
Brake disc or drum significantly and obviously worn
Advisory
3.8%class 3.4%
Tyre tread depth not in accordance with the requirements
Fail
3.0%class 2.2%
A tyre seriously damaged
Fail
3.0%class 2.0%
Child Seat fitted not allowing full inspection of adult belt
Advisory
2.8%class 2.2%

Unconfirmed issues

Reported

Owner folklore from forums and the motoring press. Most of it never shows up in an MOT, which is why this section exists at all.

N47 diesel timing chain rattle and stretch

Confirmed pattern

The four-cylinder N47 diesel (2007-2015, so mainly E90/E91/E92/E93 and early F30 320d/318d) uses plastic chain guides and a tensioner that can wear early, letting the chain stretch and rattle on start-up. Left alone it can snap and wreck the engine. BMW never called it a UK recall but ran a 2009 parts revision and a 2015 goodwill programme, and a TSB exists covering diagnosis; independent repair runs roughly £1,500-3,000, more if the engine is already damaged.

Reported from around 70-100k miles · sources: PistonHeads, Bimmerpost/babybmw forums, ABM Shop, Honest John

N20 petrol timing chain guide failure

Confirmed pattern

The turbocharged N20 four-cylinder petrol, fitted to 320i and 328i F30/F31 cars from 2012-2016, suffers from the same plastic timing chain guide problem as the diesel, cracking and breaking up over time. The giveaway is a metallic rattle for a few seconds on a cold start that fades as oil pressure builds, sometimes with fault codes P0016 or P0017. Independent specialist repair is typically £1,500-2,800; BMW dealer prices run higher.

Reported 60-100k miles, 2012-2016 build · sources: Bimmerpost, Perry's Auto, apexxengines

EGR cooler cracking and coolant loss (diesel)

Confirmed pattern

On N47, N57 and B47 diesels, the EGR cooler's internal fins can crack and let coolant leak into the intake, where it mixes with soot; in rare cases this has caused engine bay fires. Watch for a coolant level that keeps dropping with no visible leak, or the car dropping into limp mode. BMW has run genuine recalls covering this on later-build diesels (roughly 2012-2016 production), so check the car's recall status before buying; repair cost if not covered runs into four figures.

Coolant loss/limp mode, any age once affected · sources: BMW recall documentation (NHTSA/oemdtc), Trevor Burgess Autos, PistonHeads

Front suspension top mount and link knock

Partly in the MOT data

Owners of F30/F31 cars (and reportedly the newer G20) commonly report a knock or clonk from the front over bumps, usually traced to a worn front strut top mount, anti-roll bar links or the inner tie rods, becoming noticeable from around 70-80k miles. This lines up with suspension being the measured MOT fault signature for the model: it is a genuine wear point, not just an urban myth, though the exact part varies car to car so a mechanic needs to pin down which one before you pay for it.

Reported 70-80k miles · sources: Bimmerpost, BimmerFest, BMWFanatics forums

ZF8 automatic gearbox mechatronic sleeve and cold-shift harshness

Automatics only

On the ZF 8HP automatic fitted to most auto 3 Series from F30 onward, a rubber mechatronic sleeve inside the unit can harden and let fluid contaminate the electrical connections, throwing multiple transmission fault codes and leaving the car stuck in one gear or unable to select drive. Separately, harsh 1st-to-2nd shifts when cold are widely reported as normal-ish but still catch buyers out on test drives. Sleeve/mechatronic repairs run roughly £1,500-3,000; the wider gearbox itself has a good reliability reputation otherwise. Only relevant on automatic cars.

Reported across F30-G20 auto cars · sources: Bimmerpost (F30 ZF8 thread), lifeonfour.co, ASR Gearbox Repairs

Straight-six petrol valve stem seal oil burning

Emerging

On the N54/N55 straight-six petrols (335i/340i and similar), owners report blue smoke on cold start or after the car has sat for a while, caused by valve stem seals hardening with age and heat, sometimes compounded by a weak plastic PCV valve. It tends to show up from around 70-120k miles and is a specialist job because it needs BMW's locking tools, typically £1,500-3,000 in the UK once diagnosed properly. Not officially acknowledged by BMW as a defect, so treat it as a known wear item rather than a confirmed fault.

Reported 70-120k+ miles · sources: Bimmerpost/SpoolStreet forums, euroXperformance

Viewing one? Ask this

Built from the two sections above.

Start the engine stone cold and listen for a few seconds before it settles. A metallic rattle that fades as revs rise points to a worn timing chain guide (N47 diesel or N20 petrol).
Check the coolant level and look for any history of repeated coolant top-ups. Steady coolant loss with no puddle on the driveway suggests an EGR cooler leaking into the intake on a diesel.
Drive over some rough tarmac or speed bumps at low speed with the radio off. A knock or clonk from the front end points to worn top mounts, anti-roll bar links or tie rods.
On an automatic, do a full cold start and drive off immediately, feeling the 1st-to-2nd shift. A hard, jerky shift when cold is common, but any warning lights or the car refusing to select a gear means the mechatronic sleeve may already be failing.
Look for blue smoke in the mirror on a cold start or after the car has sat for a day. Points to worn valve stem seals on straight-six petrol cars, more likely on higher-mileage examples.
Check the V5 and BMW's recall checker (or ask the dealer) against the chassis and engine code. Confirms whether the EGR cooler recall or any other outstanding recall work has actually been done.
Pull up the full MOT history online, not just the pass/fail. Repeated suspension advisories year after year back up how common front-end wear is on this model.

Others in its class

Same segment (Saloons & estates), best MOT record first. Compare before you shortlist.

How it compares

Head to head with the other popular cars in its class on reliability and common faults.