How much does a BMW 430i engine replacement cost in the UK?

A reconditioned B48 engine typically costs £3,500–£5,500 supply only depending on generation, with the G22 version sitting at £3,500–£6,500. Fitting adds £1,000–£1,500. Use our calculator for a figure specific to your car.

Is the BMW 430i engine reliable?

The B48 is rated ★★★★☆ - it's one of BMW's most reliable modern engines. Unlike the N20, the B48 has the timing chain at the front and uses a more robust design, eliminating the N20's chain guide failure. However, cooling system issues (water pump, thermostat) and occasional HPFP failures have been reported.

What are the common problems with the BMW 430i?

Water pump and cooling system failures, oil filter housing leaks, and occasional high-pressure fuel pump issues are the most common. None typically lead to full engine replacement if caught early - preventative cooling system maintenance is the priority.

Is it worth replacing a BMW 430i engine, or should I scrap the car?

Against a £8,000–£16,000 430i, a £4,200 recon engine is a manageable 26–52% of the vehicle's value - worth it for a well-maintained example. Given the 4 Series' strong retained values, replacement is usually viable for vehicles in good condition.

How do I find my BMW 430i engine code?

Listed on the VIN plate and vehicle documentation. The 430i uses the B48 2.0-litre turbo petrol engine across all generations. Tell us your registration date and we'll confirm it for free.

Can I repair the B48's water pump, or does it need a new engine?

Yes - the water pump is a straightforward repair costing £500–£1,200. The B48's water pump is the most common service item on this engine; replacing it as a preventative measure at 60,000 miles is strongly recommended.

BMW 4 Series 430i2016–presentB48 Turbo Petrol

BMW 4 Series 430i Engine Replacement — Compare Prices & Get Quotes

Get quotes today from trusted UK BMW 430i specialists. Compare reconditioned, rebuilt and used B48 engines for Coupé, Convertible and Gran Coupé - supply & fit available nationwide.

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

20+ Specialists

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

20+ Specialists

BMW 430i Engines - from £2,000 to £6,500Common code: B48B20

BMW 430i Engines - from £2,000 to £6,500· Common code: B48B20

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The 430i THROUGH TIME - Era Map

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

Era Note

First-generation 430i - the B48 replaced the N20; chain at the front, no catastrophic N20-style timing guide issues.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

F32 / F33 / F36 BMW 320d F32 / F33 / F36

2016–2020B48B20 (252 bhp)★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,000–£5,500 [PLACEHOLDER - confirm vs cost sheet]First-generation 430i - the B48 replaced the N20; chain at the front, no catastrophic N20-style timing guide issues.

G22 / G23 / G26 BMW 320d G22 / G23 / G26

2020–presentB48B20 (258 bhp)★★★★☆ [NEWLY ASSIGNED - see Data Note]£3,500–£6,500 [PLACEHOLDER - confirm vs cost sheet]Modern 430i - B48 with mild-hybrid on some; same reliable architecture with slightly higher output.

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 4 Series 430i Engine Replacement Costs

Supply Only£3,500–£5,500

Fitted (Indie)£4,500–£6,800

Warranty12–24 months

Best ForMost owners - best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,000–£3,500£2,800–£4,5001–6 monthsBudget priority; vehicle under £6,000

Reconditioned Engine£3,500–£5,500£4,500–£6,80012–24 monthsMost owners - best cost/warranty balance

Rebuilt Engine£4,500–£6,500£5,500–£7,80012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£8,000–£12,000£9,500–£14,00024–36 monthsInsurance jobs, warranty claims

Labour estimate: Fitting a 430i engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer).

Common Problems With BMW 320d Engines

Ready to Compare?

Get Matched With a Vetted BMW Specialist

20+ vetted BMW specialists, every 430i variant covered, with a 12-month warranty as standard.

Get My Free 430i Engine Quotes Now

BMW 430i - 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 430i - 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 SenseWater pump failure (B48)✅ Yes£500–£1,200Preventative - replace at 60,000 milesOil filter housing leak (B48)✅ Yes£400–£900Straightforward gasket replacement; catch it earlyHigh-pressure fuel pump failure (B48)✅ Yes£800–£1,500Specialist replacement; don't let misfires damage the catTiming chain wear (B48)✅ Yes£1,500–£2,500If caught early - far less common than N20 issuesOverheating damage from coolant loss⚠️ Depends£1,500–£5,000If head gasket or block damage has occurred, replacement may be cheaperCrankshaft bearing failure❌ Usually NoEngine replacementNot a common B48 failure; if it occurs, replacement is the only option

Buying This 430i? Check These First

Buy If

Full BMW service history with documented oil-change intervals
Water pump replaced at or before 60,000 miles as a preventative measure
Evidence of regular maintenance - the B48 rewards care
2020+ G22 for the most modern iteration

Avoid If

Service history shows repeated coolant top-ups with no diagnosis
Oil leaks with no record of repair
Long crank times or hesitation - potential HPFP issues
Engine warning light present with no diagnosis documentation

Closing Verdict

The 430i's B48 is a reliable, modern turbo petrol - a significant step up from the N20 it replaced. Cooling system maintenance is the key to longevity. Buy on service history and proof of preventative water pump replacement. If you're replacing, a reconditioned unit with a 12-month warranty is the sweet spot.

20+ Vetted Specialists UK Network

12-Month Warranty as Standard

Nationwide Delivery & Collection

Transparent Pricing, No Hidden Fees

Thousands of 320d Owners Helped

Buying Checklist

Before you buy a used BMW 430i (or before you commit to an engine replacement), check these:

Cold Start

Listen for any rattle on startup (timing chain - far less common than N20)

Service History

Including which engine era (B48 is the only 430i engine - verify this before purchase)

Coolant Level

Is the coolant low with no visible leak? Water pump or thermostat housing risk

Oil Leaks

Check for oil spots under the car or a burning oil smell (oil filter housing leak)

Turbo Boost

Test acceleration; any hesitation, lag, or whistling?

HPFP Health

Long crank times? Hesitation? HPFP issues are a known occasional failure

Engine Warning Light

Have codes been read? Any unresolved cooling or fuelling issues?

MOT History

Check for emissions-related failures; the B48 should pass easily if well-maintained

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

B48B20

Years2016–2020

Power252 bhp / 350 Nm

2025 Enquiries- (pattern data)

Avg. Recon Cost£3,000–£5,500 [PLACEHOLDER]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

B48B202016–2020252 bhp / 350 Nm- (pattern data)£3,000–£5,500 [PLACEHOLDER]

B48B202020–present258 bhp / 400 Nm- (pattern data)£3,500–£6,500 [PLACEHOLDER]

Technical Specs

B48

Displacement1,998cc

Cylinders4-cylinder inline

Compression Ratio10.2:1

Fuel SystemDirect injection

TurbochargerSingle twin-scroll turbo

Market Intelligence

Most Common Failure

Water pump and cooling system issues

40%

of B48 enquiries

[PATTERN DATA]

Average Enquiry Mileage

52,000

miles

[PATTERN DATA]

Average Replacement Cost

£4,200

reconditioned, supply only

[PLACEHOLDER - confirm vs cost sheet]

Most Requested Engine Code

B48B20

[BMW-VERIFIED]

Peak Enquiry Season

Summer

cooling system issues worsen in hot weather

[PATTERN DATA]

Regional Demand

South East22%

London20%

North West14%

PATTERN DATA

Regional Demand Breakdown

22%South East

20%London

14%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.

Find the best BMW 430i engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW 430i Engine Prices Now

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available