Every BMW 8 Series engine across two generations and three body styles - from the M70 V12 of the original E31 to the B58 straight-six and N63 V8 of the modern G15. Real UK replacement costs, known failure patterns, and honest ownership economics for BMW's grand tourer flagship. Backed by 150+ real UK 8 Series engine enquiries in 2025 [BMW-VERIFIED].
Explore 8 Series Engines150+ Enquiries (2025) [BMW-VERIFIED]
2 Generations, 3 Body Styles
10+ Engine Codes
Part of Engine Finders
★★★½ (3.5/5)
⚠️ The 8 Series rule - grand tourer, grand bills: an N63 recon at £7,000–£12,000 against a £30,000 used G15 850i is 23–40% of the car's value - ⚠️ watch. Against a £100,000 G16, the same repair is just 7–12% - ✅ safe. The E31 is now a classic where engine work is restoration, not repair.
★★★☆☆ - the B58 straight-six is the modern gold standard; the N63 V8 carries the hot-vee caveats; the E31's V8s and V12s are ageing but fundamentally robust.
B58B30 (840i) - the most dependable modern BMW engine - and the M70/M73 V12 in the E31, which are surprisingly durable
N63B44 (M850i) - timing chain guides, valve stem seals, turbo failures, excessive oil consumption
G15 840i with B58 - the straight-six is bulletproof, the chassis is magnificent, and the V8 caveats don't apply
G15 M850i with N63 - 523 bhp of twin-turbo V8, but budget £7,000–£12,000 for a recon and buy the best warranty
£5,500 reconditioned, supply only [BMW-QUOTE]
N63 oil consumption / timing chain guides - shared-platform data [BMW-VERIFIED]
👑 The Flagship GT - BMW's most expensive non-M model and the car with the highest parts bills in the range
One-line verdict:
The 8 Series is BMW's grand tourer flagship - beautiful, powerful, and expensive to keep. The B58 840i is the sensible choice; the N63 M850i is the emotional one. On the modern car, buy the straight-six unless you have the budget for V8 bills. On the E31, buy the V12 and treat it as a restoration project.
Generations
2 (E31 1990–1999, G14/G15/G16 2018–2026)
Years Produced
1990–1999, 2018–2026
Engine Codes Tracked
10+
Fuel Types
Petrol, Diesel (modern), Mild-Hybrid (2020+)
Most Enquired Engine (2025)
N63B44 / B58B30 - shared-platform dataBMW-VERIFIED
Most Reliable
B58B30 (840i) / M70/M73 V12 (E31)
Highest-Risk
N63B44 (M850i) - timing chain guides, valve stem seals, turbo failure
Typical Replacement Cost
£2,800–£12,000 reconditionedBMW-QUOTE
Typical Host Value
£15,000 (E31 project) – £100,000+ (new G16)
Overall Rating
★★★½ 3.5/5
3.9/5
A perfect blend of performance, engineering excellence, and drivability.
Two generations, thirty years apart, and one grand touring mission. The original E31 is now a collector's classic; the modern G14/G15/G16 is a technological masterpiece. Choose your era - and your budget.
| Pre-2013 (E90/F30 early) | 2013-2015 (F30 pre-LCI) | 2016+ (F30 LCI / G20) | Our position | |
|---|---|---|---|---|
| Core diesel | The 3 Series we recommend for daily ownership | |||
| Core petrol |
Read the full comparison: BMW 8 Series 840i vs M850i
Every engine ever fitted to a BMW 8 Series - verified codes, specifications and real UK ownership data.
| Engine Code | Family | Fuel | Disp. | Power | Years | Gen. | Reliability | 2025 Enquiries | Avg. Recon Cost |
|---|---|---|---|---|---|---|---|---|---|
| M60B40 | M60 | Petrol | 4.0L | 282 bhp | 1990–1994 | E31 (840Ci) | ★★★★★ | - (pattern data) | £3,000–£6,000 |
| M62B44 | M62 | Petrol | 4.4L | 286 bhp | 1995–1999 | E31 (840Ci) | ★★★★★ | - (pattern data) | £3,000–£6,000 |
| M70B50 | M70 | Petrol | 5.0L | 296 bhp | 1990–1994 | E31 (850i) | ★★★★★ | - (pattern data) | £4,000–£8,000 |
| M73B54 | M73 | Petrol | 5.4L | 322 bhp | 1994–1999 | E31 (850Ci) | ★★★★★ | - (pattern data) | £4,500–£8,000 |
| S70B56 | S70 | Petrol | 5.6L | 380 bhp | 1992–1996 | E31 (850CSi) | ★★★★★ | - (pattern data) | £8,000–£14,000 |
| B58B30 | B58 | Petrol | 3.0L | 333–340 bhp | 2018–2026 | G14, G15, G16 (840i) | ★★★★★ | 540 JLR-wide [BMW-VERIFIED] | £3,800–£6,000 |
| B57D30 | B57 | Diesel | 3.0L | 315–340 bhp | 2018–2026 | G14, G15, G16 (840d) | ★★★★★ | 460 JLR-wide [BMW-VERIFIED] | £5,000–£8,000 |
| N63B44 | N63 | Petrol | 4.4L | 523 bhp | 2018–2026 | G14, G15, G16 (M850i) | ★★★★★ | 440 JLR-wide [BMW-VERIFIED] | £7,000–£12,000+ |
| S63B44 | S63 | Petrol | 4.4L | 600+ bhp | 2019–2026 | G14, G15, G16 (M8) | ★★★★★ | 410 JLR-wide [BMW-VERIFIED] | £9,000–£14,000+ |
Showing 9 of 9 engine codes
iAll enquiries are from 2025 (to date) and verified via our internal system. Recon costs are supply only and exclude fitting.
How we collect engine dataThe complete database of BMW 3 Series engine codes with real UK enquiry data, fitted models, and replacement cost insights.
Every figure below is powered by 24,650+ real UK owner enquiries in 2025. This is data you won't find anywhere else.
Enquiry volumes:
EM_Proprietary_Data_2025.txt [EM-VERIFIED]
Costs:
Table A - Engine Replacement Economics [EM-QUOTE]
Engine codes:
Cross-referenced from your existing data
The six most common failure patterns across the 8 Series range - symptoms, costs and urgency.
01The defining modern 8 Series issue - plastic timing chain guides break apart, sending metal fragments through the engine. Rattling on cold start is the warning; ignored, piston-to-valve contact destroys the engine. Affects G14/G15/G16 M850i. £7,000–£12,000+ recon.
Learn more
02The N63's companion failure - worn valve stem seals cause blue smoke on startup and excessive oil consumption (1L per 1,000 miles). Affects M850i. Often requires engine-out repair.
Learn more
03The N63's hot-vee design causes turbocharger failure from excessive heat and poor oil return. High-pressure fuel pumps can fail, dumping raw fuel into cylinders. Affects M850i.
Learn more
04The B58's known weak point - coolant expansion tank leaks and water pump failures. Affects G14/G15/G16 840i (2018+). £400–£800 repair, not catastrophic if caught early.
Learn more
05The B57 diesel's primary weak points - DPF clogging on urban-driven cars and injector issues. Affects G14/G15/G16 840d (2018+). Well-documented, repairable.
Learn more
06The original 8 Series' common non-engine issues - complex electronics (EDC, ABS, airbag modules) and cooling system plastic components degrade. Check everything on any E31.
Learn moreCatastrophicstop driving, specialist inspection immediately
Immediatebook inspection now
Monitorbook inspection soon
Lowplan at next service
150++
Total Enquiries in 2025
[BMW-VERIFIED]
BMW 8 Series G14/G15/G16 enquiries
Rising - used 840i cars entering affordable range[PLACEHOLDER - YoY %]
BMW 8 Series E31 enquiries
Stable - collector market, not failure-driven[PLACEHOLDER - YoY %]
N63B44 enquiries (JLR-wide)
Stable - the N63's reputation is well-known[PLACEHOLDER - YoY %]
B58B30 enquiries (JLR-wide)
Rising[PLACEHOLDER - YoY %]
Interesting insight: The 8 Series generates fewer enquiries than any other BMW model in our dataset - and that's a good thing. The B58-powered 840i owners barely feature in the data; the N63-powered M850i owners are the core of the enquiry volume. The B58 is proving as reliable in the flagship GT as it is in the 3 Series. (Editorial synthesis - specialist sense-check before publishing.)
The M850i's N63 V8 drives the majority of 8 Series enquiries - timing chain guides, valve stem seals, turbo failures and HPFP issues. These cars are now entering affordable used territory (£30,000–£50,000 for a used M850i), but the £7,000–£12,000+ recon bill means buyers need to budget accordingly. The 840i is the sensible choice; the M850i is the emotional one. (Editorial synthesis.)
The E31 is a different story entirely - enquiries are from collectors and enthusiasts, not owners facing unexpected failures. The V12s are appreciating assets; the V8s are rising classics. Engine work on an E31 is restoration, not repair. (Editorial synthesis.)
Editorial Pull-Quote
“If you buy one 8 Series based on this page, buy a G15 840i with the B58 straight-six - it's the most dependable engine ever fitted to the 8 Series, delivers 340 bhp and 33 mpg, and the chassis is magnificent. If the V8 is calling you, budget £7,000–£12,000 for an N63 recon and buy the best warranty you can find. And on an E31, buy the V12 and treat it as a restoration - the values are only going one way.”
Real UK pricing for used, reconditioned and rebuilt engines - supply only, with labour guidance.
| Variant | Engine Code | Used (Supply) | Reconditioned (Supply) | Rebuilt (Supply) | Labour Hours |
|---|---|---|---|---|---|
| 840Ci (M60/M62) | M60B40 / M62B44 | £2,000–£4,000 | £3,000–£6,000 | £5,000–£8,000 | 16–20 hrs |
| 850i (M70 V12) | M70B50 | £2,500–£4,500 | £4,000–£8,000 | £6,500–£10,000 | 18–24 hrs |
| 850Ci (M73 V12) | M73B54 | £2,800–£5,000 | £4,500–£8,000 | £7,000–£11,000 | 18–24 hrs |
| 850CSi (S70 V12) | S70B56 | £5,000–£10,000 | £8,000–£14,000 | £12,000–£18,000 | 20–26 hrs |
N47D20C, B47D20A, N57D30, B58B30 figures [BMW-QUOTE]; older engines [PLACEHOLDER - confirm vs cost sheet].
Fitting a BMW 8 Series engine typically takes 10–24 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [BMW-QUOTE]. The 8 Series rule - grand tourer, grand bills: A £7,000–£12,000+ N63 recon against a £35,000 used G15 M850i sits at 20–34% of the car's value - ⚠️ watch. Against a £100,000 new G16, the same repair is just 7–12% - ✅ safe. Against a £70,000 M8, a £9,000–£14,000+ S63 recon is 13–20% - ✅ safe. Our 70% BMW threshold is the line: below 70% is safe; above it, run the maths carefully. The B58 840i is the sweet spot - the most dependable engine in the range, with recon costs that are a fraction of the V8's. On an E31 V12, treat engine work as restoration - the values justify the investment.
Value the car first; the engine decision follows.
All prices in GBP (£) • Supply only • Subject to availability and condition
From the original M10 to today's advanced B-series, explore how engineering, emissions and performance shaped every generation of 3 Series engines.
BMW's flagship GT launched with the M70 V12 - the first production V12 from BMW. The V8 arrived in 1993 (840Ci) as a more affordable option.
The M70 and M73 V12s are surprisingly durable - 200k+ miles is possible with proper maintenance. The S70 in the 850CSi is one of BMW's rarest and most valuable engines.
BMW discontinued the E31 in 1999 due to poor sales - the 6 Series (E63/E64) replaced it as the grand tourer. The 8 Series nameplate lay dormant for nearly two decades.
During this period, the E31 became a cult classic. Values bottomed out around 2010 and have been rising since - the V12 cars are now serious collector's items.
BMW revived the 8 Series in 2018 on the CLAR platform. The B58 straight-six arrived in the 840i, the N63 V8 in the M850i, the B57 diesel in the 840d, and the S63 in the M8.
The B58 is the most dependable engine ever fitted to an 8 Series - no V8 caveats, robust cooling, and proven reliability from the 3 Series and 5 Series. The N63 still carries the hot-vee caveats; the S63 is the full-fat M experience.
All engine reliability insights and failure patterns are based on 826+ verified enquiries in 2025. Data covers the UK market. [BMW-VERIFIED]
Different buyers, different priorities. Here is our verdict on who the BMW 8 Series is perfect for - and who should think twice.
The 8 Series is built for this - the G15 840i with the B58 delivers 340 bhp, 33 mpg, and wafting comfort across European motorways. The B58 is bulletproof; the chassis is magnificent. The 840i is the perfect GT - powerful enough, economical enough, and the most dependable engine in the range.
The 8 Series is a grand tourer, not a commuter car - it's long, wide, and thirsty (especially the V8s). The 840d with B57 is the most sensible choice, but the 5 Series does the commuting job better. Buy an 840i if you must, but the 5 Series is the sensible choice.
One of the most dangerous badges on this site for a tight budget. A £30,000 used M850i is not a cheap 8 Series - it's an expensive one with the first year's bills prepaid by nobody. A £35,000 840i is the bargain; a £30,000 M850i without a warranty is the trap.
The M8 with the S63 is the full-fat experience - 600+ bhp, 3.2s to 60, and a V8 roar that justifies the bills. The M850i with the N63 is the warm-up act - 523 bhp and 80% of the M8's performance for 60% of the price. Buy the best warranty you can find.
The E31 V12 is a rising classic - the M70/M73 cars are the ones to buy, and values are only going one way. A G15 840i with the B58 is the modern keeper - the last of the ICE grand tourers before electrification. Both are worth proper investment.
Real talk. The right BMW 8 Series for you depends on your budget, your mileage, and your patience for maintenance. Use the data on this page to make the right call - and avoid expensive mistakes.
Rattling on cold start from an N63? Coolant loss from a B58?
On the 8 Series, the answer swings on your car's value and which engine you have - a £35,000 used M850i and a £100,000 new G16 face very different economics. Get a personalised repair-vs-replace verdict using real UK cost data.
The smarter way to decide: Get a personalised repair-vs-replace verdict using real UK cost data.
Launch the BMW diagnostic calculator with BMW 8 Series pre-selected.
We'll identify it first.
Identification is the first step inside the tool.
We'll pinpoint your exact engine code before running the diagnostics.
Our calculator compares real repair and replacement costs against your car's value - so you know the financially smarter move.
Built on Real Data - 150+ BMW 8 Series enquiries in 2025 alone [BMW-VERIFIED] - covering two generations and three body styles. Nobody has seen more UK 8 Series engine decisions across the full range.
We Tell You When Not to Repair - On a used M850i without a warranty, sometimes the honest answer is walk away. We'll give you that answer for free - if the recon cost exceeds 70% of your car's value, we'll say so before you spend.
Vetted BMW Specialists - 20+ vetted BMW specialists across the UK, specifically assessed on N63 timing chain guide assessment, B58 diagnostics, and E31 V12 restoration work. Not generalist garages - BMW grand tourer specialists.
Part of Engine Finders - the UK's leading engine replacement marketplace.
Read our in-depth BMW 3 Series vs 5 Series reliability guide.
Everything you need to choose with confidence.
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