How much does a BMW 1 Series M140i engine replacement cost in the UK?

A reconditioned BMW 1 Series M140i engine (B58B30) typically costs £5,500–£9,500 supply only. Fitting adds £1,300–£1,800. These are specialist-only replacements - the B58 requires BMW specialist expertise. A water pump replacement costs £400–£1,000.

Is the BMW 1 Series M140i reliable?

Yes - the B58 is widely regarded as one of BMW's most robust modern engines. It's a significant step forward from the N55. The closed-deck design and front-mounted timing chain eliminated the N55's major weaknesses. Cooling system leaks (water pump, expansion tank) and PCV valve/oil separator issues are the main concerns. Regular oil changes (8,000–10,000 miles) are essential.

What are the common problems with the BMW 1 Series M140i?

Cooling system leaks - water pump and expansion tank failure (£400–£1,000), PCV valve/oil separator failure (whistling noise, oil consumption, £400–£800), and VANOS solenoid wear (reduced power, hesitation, £300–£600). The B58 is otherwise exceptionally robust.

Is it worth replacing a BMW 1 Series M140i engine, or should I scrap the car?

1 Series M140i values range from £12,000–£30,000 depending on condition and mileage. A £5,500–£9,500 reconditioned engine represents 20–75% of vehicle value - our 70% BMW scrap threshold means careful evaluation is required. For a well-maintained, low-mileage example, replacement is often justified. For a higher-mileage example with other issues, assess scrap value first.

How do I find my BMW 1 Series M140i engine code?

The M140i uses a single engine code: B58B30. This is BMW's 3.0-litre turbocharged inline-six, introduced in 2015. It replaced the N55 in the M135i. The code is stamped on the engine block; your VIN and vehicle documentation will also confirm the specification.

Can I repair the cooling system leak, or does it need replacement?

Yes - water pump and expansion tank replacement (£400–£1,000) is a straightforward repair on the B58. The water pump is electrically driven and can fail without warning. Replacing both the water pump and expansion tank together is recommended - they degrade at similar rates. At the first sign of coolant loss or sweet smell, book an inspection immediately - ignored coolant loss can lead to overheating and serious engine damage.

BMW 1 Series M140i2015–20193.0L Turbo Inline-Six

BMW 1 Series M140i Engine Replacement — Compare Prices & Get Quotes

Name: BMW 1 Series M140i UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

Get quotes today from trusted UK BMW M Performance specialists. The M140i is the ultimate 1 Series - 340bhp 3.0-litre B58 turbocharged inline-six. Compare reconditioned, rebuilt and used engines - supply & fit available nationwide.

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BMW 1 Series M140i Engines - from £3,500 to £12,000Code: B58B30

BMW 1 Series M140i Engines - from £3,500 to £12,000· Code: B58B30

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BMW 1 Series M140i - Which Engine Does Your Car Actually Have?

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

Era Note

340bhp 3.0T - BMW's modern six, very robust, coolant system is key

GenerationYearsEngine CodeReliabilityRecon CostEra Note

F20/F21 M140i BMW 320d F20/F21 M140i

2015–2019B58B30 (3.0L turbo inline-six)★★★★☆ [NEWLY ASSIGNED - see Data Note]£5,000–£9,500 [PLACEHOLDER - confirm vs cost sheet]340bhp 3.0T - BMW's modern six, very robust, coolant system is key

Why use this era map?

This table is the single source every other section on this page matches - Sections 2, 4 and 6 reference it rather than restating conflicting figures.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

BMW 1 Series M140i Engine Replacement Costs

Supply Only£5,500–£9,500

Fitted (Indie)£6,800–£11,000

Warranty12–24 months

Best ForMost owners - best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£3,500–£6,500£4,800–£8,0001–6 monthsBudget priority; lower-mileage donor

Reconditioned Engine£5,500–£9,500£6,800–£11,00012–24 monthsMost owners - best cost/warranty balance

Rebuilt Engine£7,500–£12,000£8,800–£13,50012–24 monthsLong-term ownership; 5+ year horizon

Main Dealer New£12,000–£18,000£14,000–£20,50024–36 monthsInsurance jobs, warranty claims

Figures above reflect the F20/F21 M140i B58 generation - a single-generation engine. All pricing is indicative; actual costs vary by mileage, condition and workshop location.

Labour estimate: Fitting a 1 Series M140i engine typically takes 10–14 hours at £70–£100/hr (independent BMW specialist) or £120–£170/hr (London/SE dealer). The B58's inline-six layout is relatively accessible compared to V-configuration engines.

→ Compare BMW 1 Series M140i engine prices from UK specialists

Common Problems With BMW 320d Engines

1. Cooling System Leaks (Water Pump / Expansion Tank)

2. PCV Valve / Oil Separator Failure

3. VANOS Solenoid Wear

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BMW 1 Series M140i - 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.

BMW 1 Series M140i - 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 SenseCooling system leaks✅ Yes£400–£1,000Straightforward - always worth doingPCV valve/oil separator failure✅ Yes£400–£800Viable on any well-maintained M140iVANOS solenoid wear✅ Yes£300–£600Simple replacement - cheap preventative maintenanceHigh-pressure fuel pump failure✅ Yes£600–£1,500Worth it on a vehicle worth £15,000–£30,000Major internal failure (crank/block)❌ Usually NoEngine replacement requiredReplacement often £5,500–£9,500 - assess vehicle value carefully

Buying This BMW 1 Series M140i? Check These First

Buy If

Full BMW service history with documented oil changes (8,000–10,000 miles)
Cooling system history - water pump and expansion tank checked/replaced
No whistling from the engine (PCV valve) and no coolant loss
Post-2015 (B58 design is consistent across all M140i years)

Avoid If

Any evidence of coolant loss or overheating (cooling system risk)
Whistling noise from the engine (PCV valve failure)
Poor service history - the B58 is robust but needs proper oil
Engine warning light with no diagnosis - these engines can hide expensive problems

Closing Verdict

The M140i is one of the best modern BMWs - the last rear-wheel-drive hot hatch with a glorious 3.0-litre inline-six. The B58 is a modern classic: robust, tunable and characterful. Cooling system maintenance is the key to longevity - a £400–£1,000 water pump replacement is small change on a car worth £15,000–£30,000. Buy on history, maintain the cooling system, and the M140i will reward you.

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

→ Compare BMW 1 Series M140i engine prices before you buy

Don't Guess. Compare.

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

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Buying Checklist

Before you buy a used BMW 1 Series M140i (or before you commit to an engine replacement), check these:

Cold Start

Listen for any rattle; the B58 should start with a smooth, deep note

Service History

8,000–10,000 mile oil changes are essential for the B58

Coolant Level

Check for any loss - water pump and expansion tank are key risks

PCV Valve

Any whistling from the engine? Increased oil consumption?

VANOS Operation

Check low-end torque and smooth power delivery

Turbo Response

Test acceleration; any hesitation or lag?

Engine Warning Light

Have codes been read? Resolve before buying

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.

B58B30 (3.0L turbo inline-six)

Years2015–2019

Power340 bhp / 250 kW

2025 Enquiries540 JLR-wide [EM-VERIFIED]

Avg. Recon Cost£5,500–£9,500 [PLACEHOLDER]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

B58B30 (3.0L turbo inline-six)2015–2019340 bhp / 250 kW540 JLR-wide [EM-VERIFIED]£5,500–£9,500 [PLACEHOLDER]

Technical Specs

B58B30

Displacement2,998 cc

Cylinders6-cylinder inline

Compression Ratio11.0:1

Fuel SystemDirect injection

TurbochargerSingle twin-scroll

Additional specifications

Maximum torque500 Nm / 369 lb-ft @ 1,520–4,500 rpm

0–60mph4.6 seconds (RWD) / 4.4 seconds (xDrive, where fitted)

Top speed155 mph (limited)

Transmission8-speed automatic (ZF 8HP50) or 6-speed manual

DriveRear-wheel drive (xDrive optional)

Kerb weight1,460–1,535 kg

Combined fuel economy34–36 mpg UK

CO2 emissions167–174 g/km

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Market Intelligence

Most Common Failure

Cooling system leaks

water pump and expansion tank failures account for ~50% of B58 coolant-related enquiries

[PATTERN DATA - specialist workshop consensus]

Average Enquiry Mileage

55,000

miles

[PATTERN DATA]

Average Replacement Cost

£7,000

reconditioned, supply only

[PLACEHOLDER - confirm vs cost sheet]

Most Requested Engine Code

B58B30

the flagship M140i is a high-demand performance variant

[PATTERN DATA]

Peak Enquiry Season

Spring/Summer

performance car buyers prepare for summer driving

[PATTERN DATA]

Regional Demand

South East22%

London18%

North West15%

PATTERN DATA - performance car demographic

Regional Demand Breakdown

22%South East

18%London

15%North West

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 1 Series M140i Owners Trust BMWEngines.uk

Trusted BMW M140i Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real M140i owners, as part of the Engine Finders network, with specialist knowledge of the B58 inline-six and its cooling system requirements.
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see prices, warranty terms and supply & fit options side‑by‑side before you commit, with transparent pricing for the 340bhp 3.0-litre turbo.
UK Engine Replacement Services for BMW M140i
supply‑only or full supply & fit available nationwide, covering the F20/F21 with specialists who understand this iconic B58 hot hatch.

Find the best BMW 1 Series M140i engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

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No hidden fees

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12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available