How much does a BMW 840d engine replacement cost in the UK?

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.

Is the BMW 840d engine reliable?

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.

What are the common problems with the BMW 840d?

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.

Is it worth replacing a BMW 840d engine, or should I scrap the car?

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.

How do I find my BMW 840d engine code?

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.

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

BMW 840d Engine Replacement — Compare Prices & Get Quotes

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

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

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

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

Four generations. Four 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

GenerationYearsEngine CodeReliabilityRecon CostEra Note

G14/G15/G16 (early) BMW 320d G14/G15/G16 (early)

2018–2020B57D30T0 / B57D30B★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,500–£6,500 [PLACEHOLDER]3.0L twin-turbo inline-six - 320 bhp, 680 Nm. B57 family, generally robust

G14/G15/G16 (LCI) BMW 320d G14/G15/G16 (LCI)

2020–presentB57D30T2★★★★☆ [NEWLY ASSIGNED - see Data Note]£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 UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

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 TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£3,500£2,500–£5,0001–6 monthsBudget priority; lower-mileage donor

Reconditioned Engine£3,500–£6,500£5,500–£8,50012–24 monthsMost owners - best cost/warranty balance

Rebuilt Engine£4,500–£7,500£6,500–£9,50012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£9,000–£13,000+£11,000–£15,000+24–36 monthsInsurance 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.

→ Compare 840d engine prices from UK specialists

Common Problems With BMW 320d 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)

🔴 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]

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)

🔴 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]

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)

🟠 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

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)

🟡 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

Weighing Your Options?

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840d - Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

840d - Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Can It Be Repaired?

ProblemRepairable?Typical CostWhen It Makes SenseTiming chain rattle (early detection)✅ Yes£1,200–£2,500Preventative - catches the fault before catastrophic failureTiming chain snapped❌ Usually NoEngine replacementPiston-valve contact means full replacement requiredEGR cooler coolant leak✅ Yes£0 (recall) / £600–£1,200Free under recall; straightforward replacement out of warrantyDPF clogging✅ Yes£300–£800Forced regeneration or motorway runTurbocharger failure⚠️ Sometimes£1,500–£3,000Viable 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.

Don't guess.Get the right engine at the right price.

→ Compare 840d engine prices before you buy

Don't Guess. Compare.

Get real quotes from vetted UK specialists and make the right call for your 320d.

→ Compare 840d engine prices before you buy

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Buying Checklist

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

Cold Start

Listen for rattling or metallic noise (timing chain tensioner warning)

EGR Recall

Verify EGR cooler recall completion - this is critical and affects BMW diesel engines globally

DPF Health

Check for DPF warning lights; short journeys are a red flag

Service History

Including the B57 engine and confirmed BMW-approved oil changes

Oil Leaks

Look for oil residue around the engine; B57s are generally tight but check anyway

Engine Warning Light

Have codes been read? Look for timing, EGR or DPF-related codes

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 320d pitfalls.

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

BMW 320d Engine Codes

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

B57D30T0 / B57D30B

Years2018–2020

Power320 bhp (235 kW) / 680 Nm

2025 Enquiries- (pattern data)

Avg. Recon Cost£3,500–£6,500【PLACEHOLDER】

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

B57D30T0 / B57D30B2018–2020320 bhp (235 kW) / 680 Nm- (pattern data)£3,500–£6,500【PLACEHOLDER】

B57D30T22020–present340 bhp (250 kW) / 700 Nm- (pattern data)£3,500–£6,500【PLACEHOLDER】

Technical Specs

B57D30T2 - current generation

Displacement2,993 cc (3.0L)

Cylinders6-cylinder inline

Bore84 mm / Stroke: 90 mm

Compression Ratio16.5:1

ValvetrainDOHC, 4 valves per cylinder, chain-driven

Fuel SystemCommon-rail direct injection

TurbochargerTwin-turbo (TwinPower Turbo)

Mild Hybrid48V starter-generator (11 hp) on LCI models

0-62 mph5.1 seconds

Top Speed155 mph (limited)

Fuel Economy47.1–47.9 mpg (combined)

EmissionsEuro 6d

→ Compare 840d engine prices for your BMW

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Market Intelligence

Most Common Failure

Timing 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

London22%

South East18%

North West (12%)【PATTERN DATA】

Regional Demand Breakdown

22%London

18%South East

BMW 320d - Frequently Asked Questions

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.

Why UK BMW 840d Owners Trust BMWEngines.uk

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supply-only or full supply & fit available nationwide, covering every G14/G15/G16 840d since 2018.

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No hidden fees

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Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available