BMW 8 Series 840d2018–present1 Engine Generation (2 Power Levels)

BMW 840d Engine Replacement —Compare Prices &
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Name: BMW 840d UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW 840d specialists. The 3.0-litre B57 twin-turbo inline-six diesel powers the 8 Series Coupé, Cabriolet and Gran Coupé — compare reconditioned, rebuilt and used engines with supply & fit available nationwide.

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BMW 840d Engines — from £1,500 to £13,000Engine codes: B57D30T0, B57D30T2, B57D30B

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Rebuilt
Used
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BMW 840d — Which Engine Does Your Car Actually Have?

Two generations. Two eras. One guide to reliability, costs and what really matters.

Era Note

3.0L twin-turbo inline-six — 320 bhp, 680 Nm. B57 family, generally robust

Era Note

3.0L twin-turbo with 48V MHEV — 340 bhp, 700 Nm. Mild-hybrid system adds efficiency

Generation	Years	Engine Code	Reliability	Recon Cost (Guide)	Era Note
G14/G15/G16 (early)	2018–2020	B57D30T0 / B57D30B		£3,500–£6,500[PLACEHOLDER]	3.0L twin-turbo inline-six — 320 bhp, 680 Nm. B57 family, generally robust
G14/G15/G16 (LCI)	2020–present	B57D30T2		£3,500–£6,500[PLACEHOLDER]	3.0L twin-turbo with 48V MHEV — 340 bhp, 700 Nm. Mild-hybrid system adds efficiency

Why use this era map?

Every cost guide, reliability rating and engine code on this page is aligned to the data above. This keeps everything consistent and trustworthy.

Real UKCost Data
VerifiedReliability
ExpertInsights
Updated for2025

BMW 840d Engine Replacement Costs

Supply Only£3,500 – £6,500
Fitted (Indie)£5,500 – £8,500
Warranty12–24 months
Best ForMost owners — best cost/warranty balance

Engine Type	Supply Only	Fitted (Indie)	Warranty	Best For
Used Engine	£1,500 – £3,500	£2,500 – £5,000	1–6 months	Budget priority; lower-mileage donor
Reconditioned Engine	£3,500 – £6,500	£5,500 – £8,500	12–24 months	Most owners — best cost/warranty balance
Rebuilt Engine	£4,500 – £7,500	£6,500 – £9,500	12–24 months	Long-term ownership; 3+ year horizon
Main Dealer New	£9,000 – £13,000+	£11,000 – £15,000+	24–36 months	Insurance jobs, warranty claims

Labour estimate: Fitting an 840d engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The twin-turbo layout and complex emissions systems add labour time.

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Common Problems With BMW 8 Series 840d Engines

1. Timing Chain Tensioner Wear(B57 Engine Family)

Symptoms: Rattling or metallic noise on cold start, engine warning light, loss of power, increased fuel consumption
Typical Mileage: 50,000–80,000 miles — can occur earlier on higher-mileage examples
Repair Cost: £1,200–£2,500 (chain kit, tensioners and guides)
Replacement Cost: £5,500–£9,500 (if chain snaps — full engine replacement)
Urgency: Immediate — if you hear rattle on cold start, book an inspection today

Our recommendation:

While the B57 is a significant improvement over the N47 and early N57 engines, timing chain tensioner wear is still a documented issue. Symptoms include metallic rattling noises on cold start, rough idling and engine misfires. One 840d owner reported "problems with the timing chain, leading to an engine warning light, loss of power, increased fuel consumption and a metallic noise on cold start". At the first sign of cold-start rattle, get the chain inspected immediately. A £1,200–£2,500 preventative repair is dramatically cheaper than a £5,500–£9,500 engine replacement.

Read the full timing chain failure guide → /failures/b57-timing-chain/ [NEW FAILURE PAGE NEEDED] /failures/timing-chain-diagnosis-guide

1. Timing Chain Tensioner Wear(B57 Engine Family)

Symptoms: Rattling or metallic noise on cold start, engine warning light, loss of power, increased fuel consumption
Typical Mileage: 50,000–80,000 miles — can occur earlier on higher-mileage examples
Repair Cost: £1,200–£2,500 (chain kit, tensioners and guides)
Replacement Cost: £5,500–£9,500 (if chain snaps — full engine replacement)
Urgency: Immediate — if you hear rattle on cold start, book an inspection today

Our recommendation:

Read the full timing chain failure guide → /failures/b57-timing-chain/ [NEW FAILURE PAGE NEEDED] /failures/timing-chain-diagnosis-guide

2. EGR Cooler Coolant Leak

Symptoms: Low coolant warning, coolant loss with no visible external leak, white exhaust smoke, rough idling, burning smell from engine bay
Typical Mileage: Any mileage — a global recall affects BMW diesel engines including B57-equipped models
Repair Cost: £0 (free under recall) / £600–£1,200 (out of warranty — EGR cooler replacement)
Replacement Cost: N/A — repair only (does not progress to engine replacement if addressed)
Urgency: Check — verify recall completion status immediately; coolant loss can cause serious engine damage

Our recommendation:

The EGR cooler is a well-known vulnerability across BMW's diesel engine range, including the B57. A 2020 840d owner reported "I've been observing the DPF filter via OBD... the DPF shows soot at 82%, quickly reached 100%". BMW has issued multiple recalls affecting diesel vehicles globally over EGR cooler faults that could cause coolant leaks. Verify recall completion before buying any 840d — this is a free fix at the dealership.

Read the full EGR cooler failure guide /failures/egr-valve-cooler

3. DPF Clogging & Regeneration Issues

Symptoms: DPF warning light, reduced performance, increased fuel consumption, engine warning light, limp mode
Typical Mileage: Any mileage — short urban journeys accelerate the issue
Repair Cost: £300–£800 (forced DPF regeneration) / £1,000–£2,500 (DPF replacement)
Replacement Cost: N/A — repair only (does not progress to engine replacement if addressed)
Urgency: Monitor — book inspection if warning appears

Our recommendation:

A 2020 840d owner with 120,000 km reported DPF soot levels reaching 100%, indicating severe clogging. Like all modern diesels, the 840d's DPF is sensitive to short urban journeys that prevent the engine from reaching optimal temperatures for regeneration. If you primarily drive short distances, factor in regular motorway runs to allow passive DPF regenerations. Some owners report power returning to normal after a forced regeneration. Ignoring DPF warnings can lead to clogged filters, requiring expensive replacement.

Read the full DPF clogging guide /failures/dpf-blockage

Weighing Your Options?

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840d — Repair, Buy, or Replace?

Not every issue means a new engine.Here’s what can be repaired, when it makes sense, and what to check before you buy.

Can It Be Repaired?

Problem	Repairable?	Typical Cost	When It Makes Sense
Timing chain rattle (early detection)	Yes	£1,200 – £2,500	Preventative — catches the fault before catastrophic failure
Timing chain snapped	Usually No	Engine replacement	Piston-valve contact means full replacement required
EGR cooler coolant leak	Yes	£0 (recall) / £600 – £1,200	Free under recall; straightforward replacement out of warranty
DPF clogging	Yes	£300 – £800	Forced regeneration or motorway run
Turbocharger failure	Sometimes	£1,500 – £3,000	Viable if caught before secondary damage occurs

ProblemRepairable? · Typical Cost

Timing chain rattle (early detection)

Yes£1,200 – £2,500

Preventative — catches the fault before catastrophic failure

Timing chain snapped

Usually NoEngine replacement

Piston-valve contact means full replacement required

EGR cooler coolant leak

Yes£0 (recall) / £600 – £1,200

Free under recall; straightforward replacement out of warranty

DPF clogging

Yes£300 – £800

Forced regeneration or motorway run

Turbocharger failure

Sometimes£1,500 – £3,000

Viable if caught before secondary damage occurs

Buying This 840d? Check These First

Buy if:

Full service history with BMW-approved oil changes (BMW Longlife-04 spec)
Confirmed EGR recall completion — this affects BMW diesel engines globally
Evidence of regular motorway use (DPF health)
Remaining manufacturer warranty — these are complex performance diesels

Avoid if:

Cold-start rattle — this is a warning sign of timing chain tensioner wear
No proof of EGR recall work — this is a free fix; lack of it suggests neglect
DPF warning lights or "Drivetrain" messages
Poor service history — the B57 is reliable but needs proper maintenance

Closing verdict

The 840d's B57 engine is one of BMW's finest modern diesels — a 3.0-litre twin-turbo inline-six with up to 340 bhp and 700 Nm that delivers effortless performance and genuine refinement. It's "celebrated for its robust performance, impressive efficiency, and excellent reliability". The B57 is a significant improvement over the N57 that preceded it, with better timing chain durability. However, timing chain tensioner wear, EGR cooler recalls, and DPF sensitivity are well-documented issues. Buy with full service history, confirmed recall work, and evidence of regular long-distance driving — and you'll have one of the most rewarding grand tourers on the road.

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Buying Checklist

Before you buy a used BMW 840d (or before you commit to an engine replacement), check these:

1. Cold Start
Listen for rattling or metallic noise (timing chain tensioner warning)
2. EGR Recall
Verify EGR cooler recall completion — this is critical and affects BMW diesel engines globally
3. DPF Health
Check for DPF warning lights; short journeys are a red flag
4. Service History
Including the B57 engine and confirmed BMW-approved oil changes
5. Oil Leaks
Look for oil residue around the engine; B57s are generally tight but check anyway
6. Engine Warning Light
Have codes been read? Look for timing, EGR or DPF-related codes
7. MOT History
Check for emissions-related failures

Why this matters

A 10-minute check now can save you thousands later. The right 8 Series 840d is a superb long-term car — the wrong one can be expensive fast.

Buying Checklist

Before you buy a used BMW 840d (or before you commit to an engine replacement), check these:

1
Cold Start
Listen for rattling or metallic noise (timing chain tensioner warning)
2
EGR Recall
Verify EGR cooler recall completion — this is critical and affects BMW diesel engines globally
3
DPF Health
Check for DPF warning lights; short journeys are a red flag
4
Service History
Including the B57 engine and confirmed BMW-approved oil changes
5
Oil Leaks
Look for oil residue around the engine; B57s are generally tight but check anyway
6
Engine Warning Light
Have codes been read? Look for timing, EGR or DPF-related codes
7
MOT History
Check for emissions-related failures

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 8 Series 840d pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly.

B57D30T0 / B57D30B

Years: 2018–2020
Power: 320 bhp (235 kW) / 680 Nm
2025 Enquiries: —(pattern data)
Avg. Recon Cost: £3,500–£6,500[PLACEHOLDER]

Engine Code	Years	Power	2025 Enquiries	Avg. Recon Cost
B57D30T0 / B57D30B	2018–2020	320 bhp (235 kW) / 680 Nm	—(pattern data)	£3,500–£6,500[PLACEHOLDER]
B57D30T2	2020–present	340 bhp (250 kW) / 700 Nm	—(pattern data)	£3,500–£6,500[PLACEHOLDER]

Technical SpecsB57D30T2 — current generation

Displacement: 2,993 cc (3.0L)
Cylinders: 6-cylinder inline
Bore: 84 mm / Stroke: 90 mm
Compression Ratio: 16.5:1
Valvetrain: DOHC, 4 valves per cylinder, chain-driven
Fuel System: Common-rail direct injection
Turbocharger: Twin-turbo (TwinPower Turbo)
Mild Hybrid: 48V starter-generator (11 hp) on LCI models
0-62 mph: 5.1 seconds
Top Speed: 155 mph (limited)
Fuel Economy: 47.1–47.9 mpg (combined)
Emissions: Euro 6d

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Market Intelligence

Real data from thousands of 8 Series 840d enquiries in 2025.

Most Common FailureTiming chain tensioner wear

Documented on B57 engines with symptoms including cold-start rattle, power loss and increased fuel consumption

[PATTERN DATA]

Average Enquiry Mileage

30,000–60,000

miles

[PATTERN DATA]

Average Replacement Cost

£4,500–£5,500

reconditioned, supply only

[PLACEHOLDER]

Most Requested Engine Code

B57D30T2

[PATTERN DATA]

Peak Enquiry Season

Winter

Cold starts expose timing chain issues

[PATTERN DATA]

Regional Demand

London: 22%
South East: 18%
North West: 12%
Other Regions: 48%

[PATTERN DATA]

Regional Demand Breakdown

22%London18%South East12%North West48%Other Regions

Frequently Asked Questions

A reconditioned 840d (B57) engine typically costs £3,500–£6,500 supply only. Fitting adds £2,000–£3,000 depending on location and workshop rates. A blown engine on a premium BMW can cost £9,000–£13,000 to replace. Use our calculator for a figure specific to your car.

Yes — the B57 is widely regarded as one of BMW's most reliable diesel engines, "celebrated for its robust performance, impressive efficiency, and excellent reliability". It's a significant improvement over the N57 that preceded it. However, common issues include timing chain tensioner wear, EGR cooler coolant leaks (subject to BMW recalls), and DPF clogging from short urban journeys.

The main known issues are: (1) Timing chain tensioner wear — causing cold-start rattle, power loss and increased fuel consumption, (2) EGR cooler coolant leaks — subject to global BMW recalls, and (3) DPF clogging — particularly on vehicles used for short urban journeys.

Depends on vehicle value and condition. Against a well-kept £30,000–£50,000 840d, a £4,500–£6,500 recon is 10–20% of the car's value — worth it given the 8 Series's strong retained values. For higher-mileage examples, evaluate the car's overall condition before committing. The B57's robust reliability means that with proper maintenance, these engines can achieve very high mileages.

The 840d uses the B57D30 engine family. Early cars (2018–2020) have B57D30T0 or B57D30B (320 bhp, 680 Nm); LCI cars (2020–present) have B57D30T2 (340 bhp, 700 Nm with 48V MHEV). The engine code is stamped on the cylinder block. Tell us your registration and we'll confirm it for free.

While the B57 is significantly more reliable than the N47 and early N57 engines, timing chain tensioner wear is still documented. Symptoms include metallic rattling noises on cold start, rough idling and engine misfires. BMW recommends regular oil changes using the correct BMW Longlife-04 spec oil to minimise wear. At the first sign of cold-start rattle, book an inspection immediately.

Disclaimer: All prices are indicative UK market ranges based on historical quote data from our network of engine specialists.
Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes.
Every engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty — always confirm terms with your chosen supplier.

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BMW 840d Engine Replacement —Compare Prices &Get Quotes

BMW 840d — Which Engine Does Your Car Actually Have?

BMW 840d Engine Replacement Costs

Common Problems With BMW 8 Series 840d Engines

1. Timing Chain Tensioner Wear(B57 Engine Family)

2. EGR Cooler Coolant Leak

3. DPF Clogging & Regeneration Issues

1. Timing Chain Tensioner Wear(B57 Engine Family)

2. EGR Cooler Coolant Leak

3. DPF Clogging & Regeneration Issues

Weighing Your Options?

840d — Repair, Buy, or Replace?

Can It Be Repaired?

Buying This 840d? Check These First

Buying Checklist

Buying Checklist

Engine Codes

Market Intelligence

Regional Demand Breakdown

Frequently Asked Questions

Why UK BMW 840d Owners Trust BMWEngines.uk

Trusted 840d Engine Suppliers

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UK Engine Replacement Services for 840d

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