Everyone says "get a 3 Series." It's the safe answer, the sensible answer, the answer people give when they haven't really thought about it. And fair enough — the 3 Series has been the benchmark compact executive saloon for so long that recommending it feels like stating the obvious.
But here's the thing nobody tells you: there are versions of this car that are genuinely excellent used buys, and versions that will quietly ruin your bank account over twelve to eighteen months. The badge is consistent. The experience is not.
This is the guide for people who actually want to know which one to buy.
Which generation first?
There have been three 3 Series generations worth talking about on the current used market.
The E90/E91 (2005–2012) is the oldest you'll realistically consider. The saloon and estate both have their fans, and there's something satisfying about the way these drive — more connected, more analogue than what came after. But they're now fifteen to twenty years old, and age is starting to tell. You're buying other people's maintenance decisions at this point. Unless you find an exceptional low-mileage example with documented history, this generation is best left to enthusiasts who know what they're getting into.
The F30/F31 (2012–2018) is where most buyers should be looking. The interior took a significant step forward, the tech actually works, and iDrive from this era is genuinely usable. Good examples are plentiful, prices are still reasonable, and you get a car that feels modern without costing modern money. This is the sweet spot.
The G20 (2019–present) is the current generation on the used market and costs accordingly. If your budget stretches to £22,000 or above, these are worth considering seriously — the interior is excellent, the tech is properly current, and the driving experience is still BMW. Below that threshold, buy a better-spec F30.
Which engine actually makes sense?
This matters more than most people expect, and getting it wrong is an expensive mistake.
The 320d is the one most people end up with, and most of the time that's the right call. The N47 diesel is refined, economical on longer runs, and has reasonable pulling power. Just know this: early N47 engines (pre-2011) had a timing chain that ran at the back of the engine — expensive to replace when it stretches, which it does. The problem was improved in later production. Check the service history carefully and budget for a chain inspection if you're looking at early examples.
The 318d is underpowered for this car. Unless the price is genuinely exceptional, it's not worth the compromise. You'll spend every motorway overtake wondering why you didn't stretch the budget.
The 320i petrol (turbocharged four-cylinder) is smoother and better suited to town and suburban use, but the N20 engine in earlier F30s had a timing chain problem of its own — the guides and tensioner can fail. Again: documented service history is not optional, it's the whole point of the inspection.
The 328i and 330i are where the car's character really comes through. More expensive to run, but if you want the 3 Series experience rather than just the 3 Series badge, these are worth the extra. The 330i with the B58 engine (2016 onwards) is particularly good — one of BMW's better modern engines.
Skip the 316i entirely unless you're buying it for someone else and budget is the only priority.
The years that matter
Within the F30 generation, 2015 onwards is where the car really hit its stride. By then the timing chain issues had been addressed, some early software quirks had been resolved, and the specification levels improved. A 2015–2018 F30 is the combination of accessible pricing and sorted engineering that makes the most sense for most buyers.
The early G20 (2019–2021) suffered from some mild teething issues with the larger infotainment system integration — nothing catastrophic, but worth being aware of. The 2022 onwards cars are largely sorted.
What goes wrong
Cooling system. The 3 Series has a reputation for cooling system components failing — water pump, thermostat housing, expansion tank. These aren't necessarily catastrophic individually, but they can stack up quickly. If a car hasn't had cooling system work done and it's got significant mileage, assume it needs doing and factor it into what you're willing to pay.
Timing chain (N47 diesel, N20 petrol). Already mentioned, but worth repeating because it's the one that catches people out. The repair bills are substantial. A full service history that includes chain inspection or replacement is worth paying a premium for.
Injector issues on higher-mileage diesels. The 320d injectors can develop faults on cars that have done real miles — the symptom is uneven running, especially from cold. Not universal, but common enough to mention.
Suspension wear on higher-spec cars. The M Sport suspension is firmer and wears faster. Worn bushes and control arm components make the car feel vague and unsettled. It's worth getting underneath and looking — or better, getting an independent inspection done.
iDrive screen delamination on older F30 cars. The anti-glare coating peels on some units, leaving a cloudy or speckled screen. It's cosmetic rather than functional, but annoying and not cheap to fix properly.
What you should actually pay
- E90/E91 (2005–2012): £4,000–£9,000 — condition and history vary enormously
- F30/F31 (2012–2015): £8,000–£14,000
- F30/F31 (2015–2018): £13,000–£20,000
- G20 (2019+): £22,000 and above
BMW main dealer service history adds real value here — more than on most cars. The brand's own service records are well-documented and easier to verify. A 3 Series with a full main dealer history commands a premium, and it's usually worth paying.
Before you go to see it
Run the MOT history. Mileage consistency across years will tell you whether the odometer is genuine. Advisories on suspension components appearing year after year tell you the car's been driven without proper maintenance. A gap in the MOT record is a question that needs an answer.
Check the MOT history before you go →
Free MOT checker at AllCarsUKJust the registration plate. Every test, every advisory, every failure, and the recorded mileage. Free, no sign-up needed.
On the test drive: get it onto a faster road. Cooling system noise, timing chain rattle from cold, and suspension play all show themselves when the car is working properly. A short town loop tells you almost nothing useful about a car like this.
Is it worth buying?
Yes — if you buy the right one. A 2015–2018 F30 320d or 320i in M Sport trim, full BMW service history, timing chain addressed, clean MOT: that's one of the best used premium saloons available at the price. It drives properly, looks properly, and holds together properly when it's been looked after.
The 3 Series deserves its reputation. But the reputation belongs to the good ones. There are enough cars on the used market that you don't need to compromise — take the time to find one with the right history and you'll wonder why you considered anything else.