How much does a BMW 4 Series G22 engine replacement cost in the UK?

A reconditioned G22 engine typically costs £2,200–£8,000 supply only [BMW-QUOTE], depending on engine -the B48 420i sits at £2,200–£4,000, while the B57 M440d can reach £8,000. Fitting adds £650–£1,300 depending on engine and specialist location. The G22's strong retained values mean replacement is almost always viable.

Which BMW 4 Series G22 engine is the most reliable?

The B58B30 straight-six in the M440i is considered the most robust engine in the G22 range -BMW's B58 has a strong reliability reputation with few reported failures. The B48 four-cylinder petrol is also highly reliable, sharing many design improvements with the B58 [PROVISIONAL -pending dedicated Engine Page].

What are the common problems with the BMW 4 Series G22?

Cooling system leaks on the B48 and B58 petrol engines are the most common issues -investigate any coolant loss immediately. The B47 and B57 diesel engines can suffer from EGR cooler failure, DPF clogging, and AdBlue system issues. The 48V mild-hybrid system on MHEV-equipped variants can develop battery or starter-generator problems.

Is the BMW 4 Series G22 reliable?

Yes, the G22 is generally reliable -it uses BMW's proven B-family engines which have an excellent reliability record compared to older BMW engines. The B58 is widely regarded as one of BMW's most reliable modern engines. The mild-hybrid systems add complexity but are increasingly proven.

Which BMW 4 Series G22 engine should I avoid?

No engine is a hard avoid, but the diesel variants require careful consideration -emission-related components can be costly to repair. The 48V MHEV system adds complexity. The M440i is expensive to maintain and replace, though it's the most reliable six-cylinder. For most buyers, the 420i or 430i petrol is the sweet spot.

How do I know if my G22 engine needs replacing?

Coolant loss is the key warning sign on B48 and B58 petrol engines -investigate any drop in coolant level immediately. On diesel variants, reduced performance or warning lights may indicate EGR cooler or DPF issues. On MHEV variants, warning lights or drivability issues may indicate 48V system failure.

Is it worth replacing a BMW 4 Series G22 engine, or should I scrap the car?

Depends on the car's value. Against a well-kept £15,000 G22, a £2,800–£5,000 B47 recon is 19–33% -well within our 70% BMW scrap threshold [BMW-VERIFIED]. Even on a lower-value example, replacement is viable. The G22's strong retained values mean engine replacement is almost always a repair decision.

How long do BMW 4 Series G22 engines last?

The B58 straight-six can exceed 150,000 miles with proper servicing. The B48 is similarly durable, with 120,000+ miles achievable. The B47 and B57 diesel families are also durable, though emission system maintenance is important. The 48V battery typically has a lifespan of 5–8 years.

What is the difference between the G22 and the F32 4 Series?

The G22 (2020–present) is the second-generation 4 Series Coupé, built on BMW's CLAR platform with updated B-family engines and 48V mild-hybrid technology. The F32 (2013–2020) was the first generation, built on the F30 platform with older N-family engines. The G22 is larger and features more advanced engine technology.

How do I find my BMW 4 Series G22 engine code?

Listed on the VIN plate and vehicle documentation; the engine code is also stamped on the engine block. Tell us your variant (420i, 430i, M440i, 420d, 430d, M440d) and we'll identify it -20+ vetted BMW specialists will confirm it for free.

G22 Engine Replacement Cost UK -Compare Quotes

Name: BMW 4 Series G22 UK Engine Enquiry Data 2025
Creator: BMWEngines.uk

BMW 4 Series G22 Engine Codes -The Complete Database

Every engine fitted to the G22 Coupé -spanning B48 four-cylinder petrols, B58 straight-six petrols, B47 four-cylinder diesels, and B57 straight-six diesels, all with eight-speed automatic transmission.

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

Overview

BMW 4 Series G22 -Overview

The G22 is the second generation of the BMW 4 Series Coupé, unveiled in June 2020 as the successor to the F32.

It shares the CLAR platform with the G20 3 Series and features a longer wheelbase, wider track, and the controversial vertical kidney grille that defines this generation's design language. The engine line-up is all-turbocharged, featuring B48 four-cylinder petrols, B58 straight-six petrols (with 48V mild-hybrid assistance on the M440i), B47 four-cylinder diesels, and B57 straight-six diesels (both with mild-hybrid technology). A significant 2024 LCI (Life Cycle Impulse) facelift brought updated power outputs, mild-hybrid electrification to more variants, and the BMW Curved Display with Operating System 8.5.

Key Facts

Platform

BMW CLAR (Cluster Architecture)

Predecessor

F32 4 Series Coupé

Successor

None (current generation)

Sibling body styles in this generation

G23 Convertible, G26 Gran Coupé

Market Intelligence

The G22 4 Series Coupé generated 120+ real UK engine enquiries in 2025 [BMW-VERIFIED], concentrated on the 420i petrol and 420d diesel as the range reaches the used market.

BMW 4 Series G22 -Overview

The G22 is the second generation of the BMW 4 Series Coupé, unveiled in June 2020 as the successor to the F32.

It shares the CLAR platform with the G20 3 Series and features a longer wheelbase, wider track, and the controversial vertical kidney grille that defines this generation's design language. The engine line-up is all-turbocharged, featuring B48 four-cylinder petrols, B58 straight-six petrols (with 48V mild-hybrid assistance on the M440i), B47 four-cylinder diesels, and B57 straight-six diesels (both with mild-hybrid technology). A significant 2024 LCI (Life Cycle Impulse) facelift brought updated power outputs, mild-hybrid electrification to more variants, and the BMW Curved Display with Operating System 8.5.

Key Facts

Platform

BMW CLAR (Cluster Architecture)

Predecessor

F32 4 Series Coupé

Successor

None (current generation)

Sibling body styles in this generation

G23 Convertible, G26 Gran Coupé

Market Intelligence

The G22 4 Series Coupé generated 120+ real UK engine enquiries in 2025 [BMW-VERIFIED], concentrated on the 420i petrol and 420d diesel as the range reaches the used market.

Best & Worst Engines

Best Petrol Overall

B58B30 (M440i xDrive, 374–387 bhp, MHEV)

“BMW's B58 straight-six is widely regarded as the most reliable modern BMW engine. Smooth, responsive, and with 48V mild-hybrid assistance for seamless stop-start. The M440i offers effortless performance with 374 bhp and 500 Nm of torque, making it the pinnacle of the G22 petrol range.”

Who it's for: enthusiasts who want the ultimate G22 experience.

Best Diesel Overall

B57D30 (M440d xDrive, 340 bhp, MHEV)

“The most powerful diesel in the G22 range -340 bhp and 700 Nm of torque from a 3.0-litre straight-six diesel with mild-hybrid assistance. Refined, effortless, and surprisingly efficient for its performance level.”

Who it's for: buyers who want diesel torque with six-cylinder refinement.

Highest Risk

B47D20 (420d, 190 bhp, MHEV)

“The B47 is significantly more reliable than the N47 it replaced, but diesel emission components (EGR cooler, DPF, AdBlue) remain a potential cost. The mild-hybrid system adds complexity versus non-hybrid alternatives.”

Who it's for: buyers who prioritise fuel economy and are willing to maintain the diesel system carefully.

Most Expensive Failure

B58B30 (M440i xDrive)

“The B58 is the most expensive engine to replace in the G22 range -a full reconditioned unit can exceed £7,000. Cooling system leaks and oil filter housing failures are the primary concerns.”

Who it's for: buyers who want six-cylinder performance and have warranty cover.

Best Value

B48B20B (420i, 184 bhp)

“The entry-level petrol is the smart buy for most UK buyers -184 bhp is more than adequate for daily driving, the B48 is proven and reliable, and running costs are significantly lower than the six-cylinder options. The 420i offers the best blend of performance, efficiency and value in the G22 range.”

Who it's for: buyers who want coupé style with sensible running costs.

Most Overlooked

B48B20B (430i, 245–258 bhp)

“The 430i sits between the 420i and M440i -and it's the sweet spot for many buyers. With 245–258 bhp and 400 Nm of torque, it's quicker than the 420i (0-62 mph in 5.8 seconds vs 7.5) without the M440i's six-cylinder running costs. The post-LCI 430i with 258 bhp is particularly impressive.”

Who it's for: buyers who want strong performance without the M440i's premium.

Best Petrol Overall

B58B30 (M440i xDrive, 374–387 bhp, MHEV)

“BMW's B58 straight-six is widely regarded as the most reliable modern BMW engine. Smooth, responsive, and with 48V mild-hybrid assistance for seamless stop-start. The M440i offers effortless performance with 374 bhp and 500 Nm of torque, making it the pinnacle of the G22 petrol range.”

Who it's for: enthusiasts who want the ultimate G22 experience.

Best Diesel Overall

B57D30 (M440d xDrive, 340 bhp, MHEV)

“The most powerful diesel in the G22 range -340 bhp and 700 Nm of torque from a 3.0-litre straight-six diesel with mild-hybrid assistance. Refined, effortless, and surprisingly efficient for its performance level.”

Who it's for: buyers who want diesel torque with six-cylinder refinement.

Highest Risk

B47D20 (420d, 190 bhp, MHEV)

“The B47 is significantly more reliable than the N47 it replaced, but diesel emission components (EGR cooler, DPF, AdBlue) remain a potential cost. The mild-hybrid system adds complexity versus non-hybrid alternatives.”

Who it's for: buyers who prioritise fuel economy and are willing to maintain the diesel system carefully.

Most Expensive Failure

B58B30 (M440i xDrive)

“The B58 is the most expensive engine to replace in the G22 range -a full reconditioned unit can exceed £7,000. Cooling system leaks and oil filter housing failures are the primary concerns.”

Who it's for: buyers who want six-cylinder performance and have warranty cover.

Best Value

B48B20B (420i, 184 bhp)

“The entry-level petrol is the smart buy for most UK buyers -184 bhp is more than adequate for daily driving, the B48 is proven and reliable, and running costs are significantly lower than the six-cylinder options. The 420i offers the best blend of performance, efficiency and value in the G22 range.”

Who it's for: buyers who want coupé style with sensible running costs.

Most Overlooked

B48B20B (430i, 245–258 bhp)

“The 430i sits between the 420i and M440i -and it's the sweet spot for many buyers. With 245–258 bhp and 400 Nm of torque, it's quicker than the 420i (0-62 mph in 5.8 seconds vs 7.5) without the M440i's six-cylinder running costs. The post-LCI 430i with 258 bhp is particularly impressive.”

Who it's for: buyers who want strong performance without the M440i's premium.

BMW 4 Series G22 -Ownership Economics

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

B48 (420i/430i)50k–100kCoolant leaks (oil filter housing, vent pipe)£500–£1,200£2,200–£4,500

Safe Bet -proven B48, reliable.

B58 (M440i)50k–100kCoolant leaks, water pump£500–£1,500£3,800–£7,000

Best Petrol -the most robust six-cylinder.

B47 (420d)60k–120kEGR cooler, DPF, AdBlue£500–£1,500£2,800–£5,000

Solid Choice -improved over N47.

B57 (430d/M440d)60k–120kEGR cooler, DPF, AdBlue£600–£1,800£4,500–£8,000

Solid Choice -refined and powerful.

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

B48 (420i/430i)50k–100kCoolant leaks (oil filter housing, vent pipe)£500–£1,200£2,200–£4,500

Safe Bet -proven B48, reliable.

B58 (M440i)50k–100kCoolant leaks, water pump£500–£1,500£3,800–£7,000

Best Petrol -the most robust six-cylinder.

B47 (420d)60k–120kEGR cooler, DPF, AdBlue£500–£1,500£2,800–£5,000

Solid Choice -improved over N47.

B57 (430d/M440d)60k–120kEGR cooler, DPF, AdBlue£600–£1,800£4,500–£8,000

Solid Choice -refined and powerful.

The G22 rule

A £2,800–£5,000 B47 recon against a £15,000–£40,000 G22 sits at 7–33% of the car's value【EM-VERIFIED】. Even on a lower-value example, that's well within our 70% BMW scrap threshold -replacement is almost always viable. The G22's strong retained values mean engine replacement is a repair decision, not a financial one. For M440i cars (£25,000–£45,000+), even the most expensive replacement is comfortably viable.

Key Takeaways

Which G22 Costs Least To Own?
B48 420i -simple four-cylinder, proven reliability, lower running costs.
Which G22 Costs Most To Own?
B58 M440i -six-cylinder running costs and higher replacement cost.
Which G22 Is Best Value?
B48 430i -strong performance, proven B48 reliability, and the sweet spot of the range.

Common Problems

01

B48

/ B58 Cooling System Leaks (Oil Filter Housing)

Affected models:

G22 420i, 430i, M440i (B48/B58 engines).

B48 / B58 Cooling System Leaks (Oil Filter Housing)

Typical failure mileage:

40,000–80,000 miles.

Root cause:

The oil filter housing on B48 and B58 engines is a known weak point -the insert in one of the oil filter housing channels is made from a material that cannot withstand constant temperature changes, leading to coolant leaks. Coolant can leak from the oil filter housing and coolant vent pipe. If ignored, this can lead to overheating and engine damage.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,500

£500–£1,000

Oil filter housing replacement, coolant system flush

Catastrophic (Replacement)

Dealer

Specialist

£5,000–£8,000

£3,800–£7,000

Full engine replacement if overheating caused damage

Our Recommendation

Have the cooling system inspected annually and investigate any coolant loss immediately -a £500–£1,000 oil filter housing replacement is dramatically cheaper than the £3,800+ engine replacement that follows if ignored. Check for coolant stains under the car or a sweet smell in the cabin.

Compare B48/B58 engine prices for your G22

02

B48

/ B58 Water Pump Failure

Affected models:

G22 420i, 430i, M440i (B48/B58 engines).

Typical failure mileage:

80,000–100,000 miles.

Root cause:

The electric water pump on B48 and B58 engines can fail prematurely -this is a known weakness across BMW's B-family engines. Failure leads to sudden overheating and potential engine damage.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£600–£1,200

£400–£800

Water pump and thermostat replacement

Catastrophic (Replacement)

Dealer

Specialist

£5,000–£8,000

£3,800–£7,000

Full engine replacement if overheating caused damage

Our Recommendation

Replace the water pump as preventative maintenance at 80,000 miles -a £400–£800 specialist job is trivial against the £3,800+ engine replacement that follows an ignored overheating event.

Compare B48/B58 engine prices for your G22

03

B47

/ B57 Diesel EGR Cooler & Emission System Issues

Affected models:

G22 420d, 430d, M440d (B47/B57 engines).

B47 / B57 Diesel EGR Cooler & Emission System Issues

Typical failure mileage:

60,000–120,000 miles.

Root cause:

The B47 and B57 diesel engines can suffer from EGR cooler failure -internal leaks allow coolant to enter the exhaust system. DPF clogging (urban driving) and AdBlue system issues are also common. BMW has issued recalls for EGR cooler issues on some models.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,500 (recall may cover)

£500–£1,000

EGR cooler replacement, DPF clean, AdBlue system service

Catastrophic (Replacement)

Dealer

Specialist

£5,000–£8,000

£4,500–£7,500

Full engine replacement if coolant contamination caused damage

Our Recommendation

Check your diesel G22's VIN against any outstanding EGR cooler recalls -if affected, the repair is free. For DPF health, ensure regular motorway driving to allow regeneration cycles to complete. Have the emission system inspected at 60,000 miles.

Compare B47/B57 diesel engine prices for your G22

04

G22

48V Mild-Hybrid System Issues

Affected models:

G22 M440i, 420d, 430d, M440d (48V MHEV-equipped variants).

Typical failure mileage:

40,000–80,000 miles.

Root cause:

The 48V mild-hybrid system adds complexity -the 48V battery, starter-generator, and associated electronics can develop issues. The 48V battery typically has a lifespan of 5–8 years.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£800–£1,500

48V battery health check, system diagnostics

Catastrophic (Replacement)

Dealer

Specialist

£3,500–£5,500

48V battery and/or starter-generator replacement

Our Recommendation

Have the 48V system inspected during annual servicing -a £500–£1,000 check is cheap insurance against a £2,800+ system replacement. The mild-hybrid system improves efficiency and refinement -protect it.

Compare G22 MHEV system prices

G22 Engine Replacement Costs -By Engine and Condition

VariantEngine CodeUsed (Supply)Reconditioned (Supply)Rebuilt (Supply)Labour Hours

420i (2.0 petrol)B48B20B£1,000–£2,000£2,200–£4,000£3,500–£5,50010–14 hrs

430i (2.0 petrol)B48B20B£1,200–£2,500£2,500–£4,500£4,000–£6,00010–14 hrs

M440i (3.0 MHEV)B58B30£2,200–£4,000£3,800–£7,000£5,500–£9,00012–16 hrs

420d (2.0 diesel MHEV)B47D20£1,500–£2,800£2,800–£5,000£4,000–£6,50010–14 hrs

430d (3.0 diesel MHEV)B57D30£2,500–£4,500£4,500–£7,500£6,500–£9,50012–16 hrs

M440d (3.0 diesel MHEV)B57D30£2,800–£5,000£5,000–£8,000£7,000–£10,00012–16 hrs

No Generation variance from the EM_Proprietary_Data baseline figures -G22 4 Series shares the CLAR platform with the G20 3 Series, with similar engine-bay access, so costs are inherited directly per the Authority Model, with no divergence note required.

Core Variants

Diesel & Petrol Lineup

Diesel Variants

420d420d xDrive430d xDriveM440d xDrive

Petrol Variants

420i430i430i xDriveM440i xDrive

Scope note: All variants listed are G22 Coupé only. G23 Convertible and G26 Gran Coupé share the same engine families but are covered on their own Generation Pages. M440i, 420d, 430d and M440d feature 48V mild-hybrid technology. 430i power output increased from 245 bhp to 258 bhp with the 2024 LCI facelift.

Diesel & Petrol Lineup

Diesel Variants

420d420d xDrive430d xDriveM440d xDrive

Petrol Variants

420i430i430i xDriveM440i xDrive

Scope note: All variants listed are G22 Coupé only. G23 Convertible and G26 Gran Coupé share the same engine families but are covered on their own Generation Pages. M440i, 420d, 430d and M440d feature 48V mild-hybrid technology. 430i power output increased from 245 bhp to 258 bhp with the 2024 LCI facelift.

Market Intelligence

Most Requested E90 Engines (2025)

1.1. B48B20B (420i/430i)
2.2. B47D20 (420d)
3.3. B58B30 (M440i)

Most Requested E90 Variants

1.1. 420i
2.2. 420d
3.3. M440i xDrive

Average E90 Replacement Cost

£4,200 reconditioned, supply only [BMW-QUOTE]

Most Common E90 Failures

1.1. B48/B58 cooling system leaks
2.2. B47/B57 EGR/emission issues
3.3. 48V MHEV system issues

Live Feed

VehicleLocationIssueEnquiries

BMW 4 Series

G22 420i

London

Coolant leak inspection

3

enquiries

BMW 4 Series

G22 M440i

Manchester

Water pump replacement

2

enquiries

BMW 4 Series

G22 420d

Birmingham

EGR cooler recall check

2

enquiries

Updated Monthly

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK BMW 4 Series G22 Owners Trust BMWEngines.uk

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Compare G22 Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit.
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covering every variant from 420i to M440d, with supply-only or full supply & fit available nationwide.

Find the best BMW 4 Series G22 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW 4 Series G22 Engine Prices on EnginesMarket

Why UK BMW 4 Series G22 Owners Trust BMWEngines.uk

Trusted G22 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real 4 Series owners, as part of the Engine Finders network.
Compare G22 Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit.
UK Engine Replacement Services for G22
covering every variant from 420i to M440d, with supply-only or full supply & fit available nationwide.

Find the best BMW 4 Series G22 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare BMW 4 Series G22 Engine Prices on EnginesMarket

BMW 4 Series G22 Engines -The Complete UK Guide

BMW 4 Series G22 Engine Codes -The Complete Database

BMW 4 Series G22 -Overview

BMW 4 Series G22 -Overview

Best &amp; Worst Engines

BMW 4 Series G22 -Ownership Economics

Common Problems

G22 Engine Replacement Costs -By Engine and Condition

Diesel &amp; Petrol Lineup

Diesel &amp; Petrol Lineup

Market Intelligence

FAQ

Why UK BMW 4 Series G22 Owners Trust BMWEngines.uk

Why UK BMW 4 Series G22 Owners Trust BMWEngines.uk

Best & Worst Engines

Diesel & Petrol Lineup

Diesel & Petrol Lineup