BMW 6 Series: Best Years and Years to Avoid
The 6 Series is a grand tourer, not a volume car, so most examples are V8s and V10s that reward careful buyers and punish careless ones. The sensible choices are the six-cylinder petrols and diesels; the V8 and V10 halo engines carry serious, well-documented cost risk. This guide splits the E63/E64, the F06/F12/F13 and the G32 Gran Turismo by generation so you can match a good example to your budget.
Quick answer
Best all-round pick: a G32 630d/640d or 640i (six-cylinder), or an F-generation 640i (N55) or 640d (N57). Be most careful with the V8 650i (N63), the E63 645i/650i (N62) and the M6 (S85 V10 or S63 V8). The straight sixes are the durable heart of the range; the big engines reward only documented, deep-pocketed buyers.
G32 (6 Series Gran Turismo) (2017-2023) Buy
Chassis: G32
The G32 is a large five-door hatch that replaced the 5 Series GT, built on the G30 5 Series platform with BMW's modular B-series engines. It is the most dependable and practical 6 Series to own, with no V8 in the UK range to worry about. Faults are mostly minor electronics, plus the usual air-suspension and diesel maintenance items to check on higher-mileage cars.
| Best years | Any G32 630d, 640d or 640i with full history is a solid buy. The 640d xDrive (B57) is the long-legged motorway choice; the 640i (B58) is the smooth petrol pick. |
| Years to watch | Very early 2017 to 2018 cars may have outstanding software and infotainment updates; check the screen and driver aids on the test drive. Inspect the self-levelling rear air suspension for leaks. |
| Engines to trust | 640i (B58), 630d (B57), 640d (B57), 630i (B48, 2.0 four-cylinder), 620d (B47, 2.0 four-cylinder) |
| Engines to check | Early cars with outstanding software updates, High-mileage diesels (EGR and DPF) |
Key risks
- Rear self-levelling air suspension can leak or fail with age; check the car sits level and rises correctly
- B57/B47 diesel DPF regeneration needs; avoid short-trip-only cars
- Occasional infotainment, software and connectivity glitches on early cars
- Large, heavy car with big alloys: budget for tyres and check for kerb damage
F06 / F12 / F13 (2011-2018) Mixed
Chassis: F06, F12, F13
The F13 coupe, F12 convertible and F06 Gran Coupe are handsome, well-built grand tourers whose running costs depend entirely on the engine. The six-cylinder 640i petrol and 640d diesel age well and are the sensible buys. The V8 650i (N63) and the M6 (S63 V8) are fast but maintenance-heavy, and need full history plus a budget for preventative work.
| Best years | A 640i (N55) or 640d (N57) with full service history is the durable, cost-sensible choice. Later cars benefit from accumulated running fixes and updated infotainment. |
| Years to watch | Any 650i (N63 V8) for coolant transfer pipe, timing-chain-guide and oil-consumption issues, and the M6 (S63 V8) for high running costs. On convertibles, check the folding roof mechanism thoroughly. |
| Engines to trust | 640i (N55), 640d (N57) |
| Engines to check | 650i (N63 V8), M6 (S63 V8) |
Key risks
- N63 V8 (650i): coolant transfer pipe, timing chain guides, injectors and high oil consumption
- S63 V8 (M6): high running costs, carbon build-up and hard-use wear; demand a full specialist history
- N55 (640i): water pump, oil filter housing gasket and VANOS solenoids are known wear items
- N57 (640d) diesel: EGR, swirl flaps and DPF issues on neglected or short-trip cars
- Convertible (F12) folding roof and electric-motor faults; test full open and close
E63 / E64 (2003-2010) Caution
Chassis: E63, E64
The E63 coupe and E64 convertible are now cheap to buy but potentially expensive to keep, and buying one is about condition and documentation, not headline price. The naturally aspirated straight six is the simpler choice; the N62 V8 and the S85 V10 M6 carry serious, well-documented failure modes. Age-related electronics and convertible-roof faults add to the risk now.
| Best years | A 630i (N52 straight six) with a strong service file is the simplest and cheapest E63/E64 to run, avoiding the V8 and V10 cost traps entirely. |
| Years to watch | The 645i and 650i (N62 V8) for valve stem seals and the coolant transfer pipe, and the M6 (S85 V10) for rod bearings, VANOS, throttle actuators and the SMG gearbox. |
| Engines to trust | 630i (N52) |
| Engines to check | 645i / 650i (N62 valve stem seals), M6 (S85 V10 rod bearings) |
Key risks
- N62 V8 (645i/650i): valve stem seals (blue smoke on start-up), coolant transfer pipe and timing chain guides
- S85 V10 (M6): rod bearings, VANOS units, throttle actuators and expensive SMG gearbox and clutch costs
- SMG single-clutch automated manual is jerky and costly to repair, and it is fitted to some 645Ci and 650i V8s, not just the M6; a manual car is preferable where offered
- Age-related electronics, cooling systems and convertible-roof faults on high-mileage cars
- Active Steering (variable-ratio front rack) is a known trap: replacement racks are scarce and very expensive, so many specialists advise avoiding cars fitted with it
- Early CCC iDrive units fail (reboots, blank screen) and the car is very battery-sensitive, throwing spurious warnings on a weak battery; later CIC units are more stable
The pick of the range
For most UK buyers, the value sweet spot is an F-generation 640d (N57) or 640i (N55) with full service history: genuine grand-touring ability without the V8 running costs. If you want the newest and most practical car, a G32 630d or 640d Gran Turismo is the safer long-term choice, with modern B-series engines and none of the V8 risk. Buyers who prefer simplicity should look at an E63 630i (N52), the cheapest 6 Series to keep on the road.
What to avoid, and why
The engines to approach with most caution are the V8 650i (N63) in the F-generation, the E63 645i/650i (N62), and both M6 units: the E63 S85 V10 and the F-generation S63 V8. The N63 is prone to coolant transfer pipe and timing-chain-guide failures and heavy oil use; the N62 to valve stem seals and coolant leaks; the S85 to rod bearings and costly SMG and VANOS work. None are automatic walk-aways, but each is a specialist ownership that needs deep documentation and a healthy maintenance fund. Cheap purchase prices on these hide potentially very large bills.
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Get your report →Bimmer.AI is designed to help you identify BMW-specific buyer risks before you travel, negotiate, or pay for an inspection. It does not replace a physical inspection by a qualified mechanic, a legal vehicle-history check (e.g. HPI Check), or independent verification of finance, stolen, or write-off status. Repair-cost ranges are indicative UK figures that vary by region, specialist, parts supply, and labour rates.
Frequently asked questions
What is the most reliable BMW 6 Series?
The six-cylinder cars are the most dependable: an F-generation 640i (N55 petrol) or 640d (N57 diesel), or a G32 6 Series Gran Turismo 630d/640d/640i. All avoid the V8 and V10 cost risks while keeping the grand-touring character. The G32 is the newest and most practical choice.
Which BMW 6 Series should I avoid?
No generation is a blanket avoid, but the V8 and V10 engines need the most caution: the 650i (N63) in the F-generation, the 645i/650i (N62) in the E63, and both M6 versions (E63 S85 V10, F-generation S63 V8). Buy these only with full specialist history and a serious maintenance budget.
Is the BMW 650i (N63) reliable?
The N63 twin-turbo V8 is powerful but maintenance-heavy, with documented coolant transfer pipe failures, timing chain guide wear, injector issues and high oil consumption. It can be owned successfully with full history and a repair fund, but it is not a cheap car to keep, so budget accordingly.
Is the E63 M6 (S85 V10) a good buy?
Only for buyers who understand its costs. The S85 V10 is a spectacular engine but needs rod bearings monitored, VANOS units and throttle actuators serviced, and the SMG gearbox and clutch maintained. Cheap purchase prices hide potentially large bills, so treat it as a specialist ownership, not a bargain.
What is the BMW 6 Series Gran Turismo (G32)?
The G32 is a large five-door hatchback built on the G30 5 Series platform, sold from 2017 to 2023 as a replacement for the 5 Series GT. In the UK it came with six-cylinder petrol (630i/640i) and diesel (630d/640d) engines, with no V8, which makes it the most practical and cost-sensible 6 Series to own.
Petrol or diesel 6 Series for the UK?
For higher mileage and motorway touring, the six-cylinder diesels (640d N57, or the G32 630d/640d B57) are efficient and durable. For lower mileage or a smoother feel, the 640i (N55) or G32 640i (B58) petrol avoids DPF and EGR concerns. Most UK buyers are best served avoiding the thirsty, maintenance-heavy V8s entirely.