How much does a BMW 6 Series F12 engine replacement cost in the UK?

A reconditioned F12 engine typically costs £4,000–£15,000 supply only [BMW-QUOTE], depending on engine -the N55 640i sits at £4,000–£7,000, while the S63 M6 V8 can reach £15,000. Fitting adds £650–£1,500 depending on engine and specialist location.

Which BMW 6 Series F12 engine is the most reliable?

The N55 3.0-litre straight-six petrol is considered the most reliable engine in the F12 range -it's a proven, well-understood design with fewer major failure modes than the V8s. The N57 diesel is also highly reliable, though the EGR cooler is a known weak point [PROVISIONAL -pending dedicated Engine Page].

What are the common problems with the BMW 6 Series F12?

Valve stem seal wear on the N63 V8 is the most significant engine problem -blue smoke on startup is the classic warning sign. The S63 V8 in the M6 can suffer from rod bearing wear. The N57 diesel can have EGR cooler and DPF issues. The N55 is the most reliable engine in the range, though HPFP and VANOS issues can occur.

Is the BMW 6 Series F12 reliable?

It depends heavily on which engine you choose. The N55 is the most reliable option -it's a proven engine with a strong track record. The N57 is also reliable, though emission system maintenance is important. The N63 V8 and S63 V8 are spectacular engines but require careful maintenance -valve stem seals and rod bearings are known weaknesses.

Which BMW 6 Series F12 engine should I avoid?

No engine is a hard avoid, but the N63 V8 requires very careful consideration -valve stem seal wear is well-documented and a full repair costs £1,500–£3,500 [BMW-QUOTE]. The S63 V8 also requires rod bearing replacement as preventative maintenance (£2,000–£3,500). For most buyers, the 640i or 640d is the sweet spot.

How do I know if my F12 engine needs replacing?

On N63 V8s, blue smoke on startup indicates valve stem seal failure -investigate immediately. On S63 M6s, a low oil pressure warning or knocking sound is critical -stop driving immediately. On N55 640is, long cranking or limp mode indicates HPFP failure. Use our diagnostic tool for a personalised assessment.

Is it worth replacing a BMW 6 Series F12 engine, or should I scrap the car?

Depends on the car's value. Against a well-kept £15,000 F12, a £4,500–£7,500 N57 recon is 30–50% -safe. Against a tired £8,000 example, the same recon is 56–94% -borderline. Our 70% BMW scrap threshold is the line [BMW-VERIFIED]. For M6 cars, even the most expensive replacement is viable given collector values.

How long do BMW 6 Series F12 engines last?

The N55 and N57 can exceed 150,000 miles with proper servicing -they are proven, durable designs. The N63 and S63 V8s can also achieve high mileages, but require more regular specialist attention -valve stem seals and rod bearings are critical maintenance items. All F12 engines are now 7+ years old.

What is the difference between the F12, F13 and F06 6 Series?

The F12 is the 2-door convertible (2011–2018), the F13 is the 2-door coupé (2011–2017), and the F06 is the 4-door Gran Coupé (2012–2018). All three share the L6 platform and most engines, but body styles differ. The G14 8 Series Convertible succeeded the F12 in 2018.

How do I find my BMW 6 Series F12 engine code?

Listed on the VIN plate and vehicle documentation; the engine code is also stamped on the engine block. Tell us your variant and production year, and we'll identify it -20+ vetted BMW specialists will confirm it for free. Note that the 650i power output increased from 407 PS to 450 PS with the LCI in 2014.

F12 Engine Replacement Cost UK -Compare Quotes

Name: BMW 6 Series F12 UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

BMW 6 Series F12 Engine Codes -The Complete Database

Every engine fitted to the F12 Convertible specifically -spanning the N55 straight-six petrol, the N57 straight-six diesel, the N63 V8 petrol, the S63 V8 in the M6, and their LCI updates.

Engine CodeFamilyFuelDisplacementPowerYears (F12)Variants (badges)Reliability2025 EnquiriesAvg. Recon Cost

N55B30AN55Petrol3.0L (2979cc)320 PS (235 kW) / 315 hp03.2011–2018640i, 640i xDrive★★★★☆ [PROVISIONAL -pending dedicated Engine Page]540 (B58) [BMW-VERIFIED]£4,000–£7,000 [BMW-QUOTE]

N63B44AN63Petrol4.4L (4395cc)407–408 PS (300 kW) / 401–408 hp03.2011–2014650i, 650i xDrive★★★☆☆ [PROVISIONAL -pending dedicated Engine Page]440 [BMW-VERIFIED] (N63)£6,000–£10,000 [BMW-QUOTE]

N63B44B (LCI)N63Petrol4.4L (4395cc)450 PS (330 kW) / 444 hp2014–2018650i, 650i xDrive★★★☆☆ [PROVISIONAL -pending dedicated Engine Page]440 [BMW-VERIFIED] (N63)£6,000–£10,000 [BMW-QUOTE]

N57D30BN57Diesel3.0L (2993cc)313 PS (230 kW) / 309 hp09.2011–2018640d, 640d xDrive★★★★☆ [PROVISIONAL -pending dedicated Engine Page]830 [BMW-VERIFIED] (N57)£4,500–£7,500 [BMW-QUOTE]

S63B44BS63Petrol4.4L (4395cc)560 PS (412 kW) / 552 hp01.2012–2018M6 Convertible★★★★☆ [PROVISIONAL -pending dedicated Engine Page]410 [BMW-VERIFIED] (S63)£9,000–£15,000 [BMW-QUOTE]

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

N55B30AN55Petrol320 PS (235 kW) / 315 hp03.2011–2018★★★★☆ [PROVISIONAL -pending dedicated Engine Page]540 (B58) [BMW-VERIFIED]£4,000–£7,000 [BMW-QUOTE]

N63B44AN63Petrol407–408 PS (300 kW) / 401–408 hp03.2011–2014★★★☆☆ [PROVISIONAL -pending dedicated Engine Page]440 [BMW-VERIFIED] (N63)£6,000–£10,000 [BMW-QUOTE]

N63B44B (LCI)N63Petrol450 PS (330 kW) / 444 hp2014–2018★★★☆☆ [PROVISIONAL -pending dedicated Engine Page]440 [BMW-VERIFIED] (N63)£6,000–£10,000 [BMW-QUOTE]

N57D30BN57Diesel313 PS (230 kW) / 309 hp09.2011–2018★★★★☆ [PROVISIONAL -pending dedicated Engine Page]830 [BMW-VERIFIED] (N57)£4,500–£7,500 [BMW-QUOTE]

S63B44BS63Petrol560 PS (412 kW) / 552 hp01.2012–2018★★★★☆ [PROVISIONAL -pending dedicated Engine Page]410 [BMW-VERIFIED] (S63)£9,000–£15,000 [BMW-QUOTE]

Overview

BMW 6 Series F12 -Overview

The F12 is the convertible body of BMW's third-generation 6 Series, unveiled at the 2011 Shanghai Auto Show.

It shares the L6 platform with the F10 5 Series and F01 7 Series, offering a luxurious grand tourer experience with a fabric roof that operates at speeds up to 40 km/h. The engine line-up featured a 3.0-litre straight-six petrol (640i), a 3.0-litre straight-six diesel (640d), a 4.4-litre V8 petrol (650i), and the S63 V8-powered M6. A late 2014 LCI facelift brought an output boost for the 650i to 450 PS and subtle styling updates. The F12 was produced until September 2018, succeeded by the G14 8 Series Convertible.

Key Facts

Platform

BMW L6 (shared with F10, F01)

Predecessor

E64 6 Series Convertible

Successor

G14 8 Series Convertible

Sibling body styles in this generation

F13 Coupé, F06 Gran Coupé

Market Intelligence

The F12 Convertible generated 120+ real UK engine enquiries in 2025 [BMW-VERIFIED], concentrated on the 640i petrol and 640d diesel as the range reaches affordable used-car territory.

BMW 6 Series F12 -Overview

The F12 is the convertible body of BMW's third-generation 6 Series, unveiled at the 2011 Shanghai Auto Show.

It shares the L6 platform with the F10 5 Series and F01 7 Series, offering a luxurious grand tourer experience with a fabric roof that operates at speeds up to 40 km/h. The engine line-up featured a 3.0-litre straight-six petrol (640i), a 3.0-litre straight-six diesel (640d), a 4.4-litre V8 petrol (650i), and the S63 V8-powered M6. A late 2014 LCI facelift brought an output boost for the 650i to 450 PS and subtle styling updates. The F12 was produced until September 2018, succeeded by the G14 8 Series Convertible.

Key Facts

Platform

BMW L6 (shared with F10, F01)

Predecessor

E64 6 Series Convertible

Successor

G14 8 Series Convertible

Sibling body styles in this generation

F13 Coupé, F06 Gran Coupé

Market Intelligence

The F12 Convertible generated 120+ real UK engine enquiries in 2025 [BMW-VERIFIED], concentrated on the 640i petrol and 640d diesel as the range reaches affordable used-car territory.

Best & Worst Engines

Best Petrol Overall

N55B30A (640i, 3.0L straight-six, 320 PS)

“BMW's N55 single-turbo straight-six is a proven, reliable engine -smooth, responsive, and with a strong torque curve from 1,300 rpm. The 640i offers effortless grand touring performance without the V8's running costs.”

Who it's for: buyers who want six-cylinder refinement with sensible running costs.

Best Diesel Overall

N57D30B (640d, 3.0L straight-six diesel, 313 PS)

“The N57 straight-six diesel is a masterpiece of refinement and efficiency -313 PS, 630 Nm of torque, and genuine 40+ mpg capability. The 640d offers the best blend of performance and economy in the F12 range.”

Who it's for: buyers who want effortless torque and long-distance cruising capability.

Highest Risk

N63B44A/B (650i, 4.4L V8, 407–450 PS)

“The N63 'hot-vee' V8 is a spectacular engine but has a reputation for heat-related failures -valve stem seal wear is the most common issue, leading to blue smoke on startup. The LCI's N63B44B is improved but still requires careful maintenance.”

Who it's for: 650i buyers with deep pockets and full service history.

Most Expensive Failure

S63B44B (M6 Convertible, 4.4L V8, 560 PS)

“The S63 V8 in the M6 is the most powerful and most expensive engine in the F12 range -rod bearing wear is a known issue on early examples, and a full replacement can exceed £15,000. The M6 is a future classic, but it comes with M-car running costs.”

Who it's for: collectors and enthusiasts who want the ultimate F12 experience.

Best Value

N57D30B (640d, 3.0L diesel, 313 PS)

“The 640d offers near-650i performance with significantly lower running costs -313 PS, 630 Nm of torque, and excellent fuel economy. It's the smart buy for anyone covering serious mileage in their grand tourer.”

Who it's for: buyers who want effortless performance with sensible economy.

Most Overlooked

N55B30A (640i, 3.0L petrol, 320 PS)

“The 640i is often overlooked in favour of the V8 650i or the diesel 640d -but it's the sweet spot for many buyers. The N55 is proven and reliable, the power is more than adequate, and running costs are significantly lower than the V8. It's the most balanced engine in the F12 range.”

Who it's for: buyers who want six-cylinder refinement without diesel clatter or V8 bills.

Best Petrol Overall

N55B30A (640i, 3.0L straight-six, 320 PS)

“BMW's N55 single-turbo straight-six is a proven, reliable engine -smooth, responsive, and with a strong torque curve from 1,300 rpm. The 640i offers effortless grand touring performance without the V8's running costs.”

Who it's for: buyers who want six-cylinder refinement with sensible running costs.

Best Diesel Overall

N57D30B (640d, 3.0L straight-six diesel, 313 PS)

“The N57 straight-six diesel is a masterpiece of refinement and efficiency -313 PS, 630 Nm of torque, and genuine 40+ mpg capability. The 640d offers the best blend of performance and economy in the F12 range.”

Who it's for: buyers who want effortless torque and long-distance cruising capability.

Highest Risk

N63B44A/B (650i, 4.4L V8, 407–450 PS)

“The N63 'hot-vee' V8 is a spectacular engine but has a reputation for heat-related failures -valve stem seal wear is the most common issue, leading to blue smoke on startup. The LCI's N63B44B is improved but still requires careful maintenance.”

Who it's for: 650i buyers with deep pockets and full service history.

Most Expensive Failure

S63B44B (M6 Convertible, 4.4L V8, 560 PS)

“The S63 V8 in the M6 is the most powerful and most expensive engine in the F12 range -rod bearing wear is a known issue on early examples, and a full replacement can exceed £15,000. The M6 is a future classic, but it comes with M-car running costs.”

Who it's for: collectors and enthusiasts who want the ultimate F12 experience.

Best Value

N57D30B (640d, 3.0L diesel, 313 PS)

“The 640d offers near-650i performance with significantly lower running costs -313 PS, 630 Nm of torque, and excellent fuel economy. It's the smart buy for anyone covering serious mileage in their grand tourer.”

Who it's for: buyers who want effortless performance with sensible economy.

Most Overlooked

N55B30A (640i, 3.0L petrol, 320 PS)

“The 640i is often overlooked in favour of the V8 650i or the diesel 640d -but it's the sweet spot for many buyers. The N55 is proven and reliable, the power is more than adequate, and running costs are significantly lower than the V8. It's the most balanced engine in the F12 range.”

Who it's for: buyers who want six-cylinder refinement without diesel clatter or V8 bills.

BMW 6 Series F12 -Ownership Economics

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

N55 (640i)50k–100kHPFP, VANOS, oil leaks£600–£2,000£4,000–£7,000

Solid Choice -proven N55, reliable.

N57 (640d)80k–150kEGR cooler, DPF£600–£2,000£4,500–£7,500

Best Diesel -refined and durable.

N63 (650i)40k–80kValve stem seals, turbo coolant£1,500–£4,000£6,000–£10,000

High Cost -spectacular V8, costly to maintain.

S63 (M6)30k–70kRod bearings, throttle actuators£2,000–£5,000£9,000–£15,000

Performance Icon -budget for maintenance.

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

N55 (640i)50k–100kHPFP, VANOS, oil leaks£600–£2,000£4,000–£7,000

Solid Choice -proven N55, reliable.

N57 (640d)80k–150kEGR cooler, DPF£600–£2,000£4,500–£7,500

Best Diesel -refined and durable.

N63 (650i)40k–80kValve stem seals, turbo coolant£1,500–£4,000£6,000–£10,000

High Cost -spectacular V8, costly to maintain.

S63 (M6)30k–70kRod bearings, throttle actuators£2,000–£5,000£9,000–£15,000

Performance Icon -budget for maintenance.

The F12 rule

A £4,500–£7,500 N57 recon against a £8,000–£25,000 F12 sits at 18–94% of the car's value【EM-VERIFIED】. On a sub-£10,000 example, that brushes our 70% BMW threshold -we'll honestly tell you to walk away. Against a well-kept £15,000+ example, the same recon drops to 30–50% -a repair decision, not a financial one. Value the car first. For M6 cars (£20,000–£40,000+), even the most expensive S63 replacement is viable given collector values.

Key Takeaways

Which F12 Costs Least To Own?
N57 640d -excellent fuel economy, fewer major failure modes than the V8s.
Which F12 Costs Most To Own?
S63 M6 -rod bearings, V8 complexity and M-car running costs add up fast.
Which F12 Is Best Value?
N55 640i -proven six-cylinder reliability, strong performance, and lower running costs than the V8.

Common Problems

01

N63

V8 Valve Stem Seal Wear

Affected models:

F12 650i, 650i xDrive (2011–2018, N63 engine).

Typical failure mileage:

40,000–80,000 miles.

Root cause:

The N63 'hot-vee' design places the turbochargers inside the V of the engine, leading to heat-related valve stem seal hardening. This causes oil to leak past the seals into the combustion chamber, resulting in blue smoke on startup and increased oil consumption. BMW issued technical service bulletins for valve seal replacement.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£3,000–£5,000

£1,500–£3,500

Valve stem seal replacement (specialist tool required)

Catastrophic (Replacement)

Dealer

Specialist

£10,000–£14,000

£6,000–£10,000

Full reconditioned N63 engine replacement

Our Recommendation

If you're buying an N63-powered F12 650i, budget for valve stem seal replacement immediately unless there's documented proof it's already been done -£1,500–£3,500 now is far cheaper than the £6,000+ engine replacement that follows if ignored. Blue smoke on startup is the classic warning sign -don't ignore it.

Compare N63 engine prices for your F12 650i

02

S63

Rod Bearing Wear (M6)

Affected models:

F12 M6 Convertible (2012–2018, S63 engine).

Typical failure mileage:

30,000–70,000 miles.

Root cause:

Early S63 engines can suffer from rod bearing wear -a known issue shared with the S65 V8 in the E9x M3. Oil starvation and clearance issues can lead to bearing failure and catastrophic engine damage. This is the single most important maintenance item on any S63-powered BMW.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£3,000–£5,000

£2,000–£3,500

Rod bearing replacement with upgraded bearings

Catastrophic (Replacement)

Dealer

Specialist

£14,000–£20,000

£9,000–£15,000

Full S63 engine replacement

Our Recommendation

If you're buying an F12 M6, budget for rod bearing replacement immediately unless there's documented proof it's already been done -£2,000–£3,500 now is dramatically cheaper than the £9,000+ engine replacement that follows a bearing failure. This is not optional; it's the defining maintenance item of the S63 V8.

Compare S63 engine prices for your F12 M6

03

N55

HPFP & VANOS Issues

Affected models:

F12 640i, 640i xDrive (2011–2018, N55 engine).

Typical failure mileage:

50,000–100,000 miles.

Root cause:

The N55 can suffer from high-pressure fuel pump (HPFP) failure and VANOS solenoid issues -though less common than on the earlier N54. HPFP failure leads to long cranking and limp mode; VANOS issues cause rough running and reduced performance.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£1,200–£2,000

£700–£1,500

HPFP and VANOS solenoid replacement

Catastrophic (Replacement)

Dealer

Specialist

£6,000–£9,000

£4,000–£7,000

Full reconditioned N55 engine replacement

Our Recommendation

Have the HPFP and VANOS system inspected at 60,000 miles -a £700–£1,500 preventative service is far cheaper than the £4,000+ replacement that follows a catastrophic failure. If you experience long cranking on startup, investigate immediately.

Compare N55 engine prices for your F12 640i

04

N57

Diesel EGR Cooler & Emission System Issues

Affected models:

F12 640d, 640d xDrive (2011–2018, N57 engine).

N57 Diesel EGR Cooler & Emission System Issues

Typical failure mileage:

60,000–120,000 miles.

Root cause:

The N57 diesel's EGR cooler can develop internal leaks, allowing coolant to enter the exhaust system. DPF clogging (urban driving) and AdBlue system issues (where fitted) are also common. BMW has issued recalls for EGR cooler issues on some models.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,500 (recall may cover)

£500–£1,000

EGR cooler replacement, DPF clean, AdBlue system service

Catastrophic (Replacement)

Dealer

Specialist

£6,000–£9,000

£4,500–£7,500

Full engine replacement if coolant contamination caused damage

Our Recommendation

Check your N57 F12's VIN against any outstanding EGR cooler recalls -if affected, the repair is free. For DPF health, ensure regular motorway driving to allow regeneration cycles to complete. Have the emission system inspected at 60,000 miles.

Compare N57 diesel engine prices for your F12 640d

F12 Engine Replacement Costs -By Engine and Condition

VariantEngine CodeUsed (Supply)Reconditioned (Supply)Rebuilt (Supply)Labour Hours

640i / 640i xDrive (3.0 petrol)N55B30A£2,000–£4,000£4,000–£7,000£5,500–£8,50012–16 hrs

650i / 650i xDrive (4.4 V8, pre-LCI)N63B44A£3,500–£6,000£6,000–£10,000£8,000–£14,00016–22 hrs

650i / 650i xDrive (4.4 V8, LCI)N63B44B£3,500–£6,000£6,000–£10,000£8,000–£14,00016–22 hrs

640d / 640d xDrive (3.0 diesel)N57D30B£2,500–£4,500£4,500–£7,500£6,500–£9,50012–16 hrs

M6 Convertible (4.4 V8)S63B44B£5,000–£9,000£9,000–£15,000£12,000–£18,00018–24 hrs

No Generation variance from the EM_Proprietary_Data baseline figures -F12 Convertible shares the L6 platform with the F10 5 Series, with similar engine-bay access, so costs are inherited directly per the Authority Model, with no divergence note required.

Core Variants

Diesel & Petrol Lineup

Diesel Variants

640d640d xDrive

Petrol Variants

640i640i xDrive650i650i xDriveM6 Convertible

Scope note: All variants listed are F12 Convertible only. F13 Coupé and F06 Gran Coupé share the same engine families but are covered on their own Generation Pages. The LCI (late 2014) brought the N63B44B with 450 PS for the 650i. M6 Convertible features the S63B44B V8 with 560 PS.

Diesel & Petrol Lineup

Diesel Variants

640d640d xDrive

Petrol Variants

640i640i xDrive650i650i xDriveM6 Convertible

Scope note: All variants listed are F12 Convertible only. F13 Coupé and F06 Gran Coupé share the same engine families but are covered on their own Generation Pages. The LCI (late 2014) brought the N63B44B with 450 PS for the 650i. M6 Convertible features the S63B44B V8 with 560 PS.

Market Intelligence

Most Requested E90 Engines (2025)

1.1. N57D30 (largest share of diesel enquiries)
2.2. N55B30
3.3. N63B44

Most Requested E90 Variants

1.1. 640i
2.2. 640d
3.3. 650i

Average E90 Replacement Cost

£5,500 reconditioned, supply only [BMW-QUOTE]

Most Common E90 Failures

1.1. N63 valve stem seal wear
2.2. S63 rod bearing wear
3.3. N57 EGR cooler failure

Live Feed

VehicleLocationIssueEnquiries

BMW 6 Series

F12 640i

London

HPFP inspection

3

enquiries

BMW 6 Series

F12 640d

Birmingham

EGR cooler recall check

2

enquiries

BMW 6 Series

F12 M6

Surrey

Rod bearing inspection

2

enquiries

Updated Monthly

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK BMW 6 Series F12 Owners Trust BMWEngines.uk

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see prices, warranty terms and supply & fit options side-by-side before you commit.
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covering every variant from 640i to M6, with supply-only or full supply & fit available nationwide.

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Why UK BMW 6 Series F12 Owners Trust BMWEngines.uk

Trusted F12 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real 6 Series Convertible owners, as part of the Engine Finders network.
Compare F12 Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit.
UK Engine Replacement Services for F12
covering every variant from 640i to M6, with supply-only or full supply & fit available nationwide.

Find the best BMW 6 Series F12 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW 6 Series F12 Engine Prices on EnginesMarket

BMW 6 Series F12 Engines -The Complete UK Guide

BMW 6 Series F12 Engine Codes -The Complete Database

BMW 6 Series F12 -Overview

BMW 6 Series F12 -Overview

Best &amp; Worst Engines

BMW 6 Series F12 -Ownership Economics

Common Problems

F12 Engine Replacement Costs -By Engine and Condition

Diesel &amp; Petrol Lineup

Diesel &amp; Petrol Lineup

Market Intelligence

FAQ

Why UK BMW 6 Series F12 Owners Trust BMWEngines.uk

Why UK BMW 6 Series F12 Owners Trust BMWEngines.uk

Best & Worst Engines

Diesel & Petrol Lineup

Diesel & Petrol Lineup