BMW X4 M40i Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK BMW X4 M40i engine specialists. Compare prices on reconditioned, rebuilt and used B58 engines for the M Performance flagship - supply & fit available across our nationwide network.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £4,500 to £8,500
Used from £2,000 · Reconditioned from £3,800 · Common codes: B58B30, B58B30O1
From £2,000
Tested, bare/short engine
From £3,800
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
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3 Simple Steps3 Simple Stepsto Finding the Best BMW X4 M40i Replacement Engineto Finding the Best BMW X4 M40i Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryBMW X4 M40i - Engine History & Specs at a Glance
The BMW X4 M40i arrived in 2018 as the performance flagship of the second-generation G02 X4 range, powered by BMW's acclaimed B58 3.0-litre turbocharged straight-six - widely considered one of the most reliable modern performance engines BMW has ever built.
Variant HistoryBMW X4 M40i - Engine History & Specs at a Glance
The BMW X4 M40i arrived in 2018 as the performance flagship of the second-generation G02 X4 range, powered by BMW's acclaimed B58 3.0-litre turbocharged straight-six - widely considered one of the most reliable modern performance engines BMW has ever built.
BMW X4 M40i
Fuel TypePetrol (MHEV from 2021)
Engine Size3.0L (2,998cc)
Power Output355-387hp (B58B30)Engine History Timeline
G02 X4 M40i launched with B58B30 engine 355hp, 500Nm, 0-62mph in 4.8 seconds
LCI facelift introduces MHT 48V mild hybrid technology; B58 output rises to 360hp with 11hp electric boost
End of G02 X4 production confirmed; B58 M40i remains the flagship petrol powertrain
Key Specs Snapshot
Fuel TypePetrol (MHEV from 2021)Engine Size3.0L (2,998cc)Power Output355-387hp (B58B30)Years Produced2018-2024Every B58 variant fitted to the BMW X4 M40i is covered below, with UK rebuilt pricing and known failure points - from early B58B30 units to the 48V MHT LCI cars.
BMW X4 M40i Engine Codes - Specifications & Replacement CostBMW X4 M40i Engine Codes - Specifications & Replacement Cost
3.0L Petrol (2018-2024)
Power Output355-387hpYears Fitted2018-2024
Compatible Trim Levels
- M40i
- M40i M Sport (standard)
- M40i MHT (48V mild hybrid from 2021)
- M40i M Pro Edition
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£2,000-£3,800
Reconditioned
Addressed known issues, tested
£3,800-£6,000
Rebuilt
Full teardown, upgraded internals
£4,500-£8,500
Common Failure
The B58's plastic oil filter housing can become brittle and develop leaks, typically from around 50,000-80,000 miles. Coolant loss from the expansion tank cap and water pump failures are also well-documented .
The B58 engine in the BMW X4 M40i is widely regarded as one of BMW's most reliable modern straight-sixes, with many examples exceeding 150,000 miles without major failures. However, several well-documented weak points - particularly around the cooling system and oil filter housing - can lead to costly repairs if not caught early. Every rebuilt B58 engine supplied through EnginesMarket includes upgraded components designed to address these failure points, plus a minimum 12-month unlimited-mileage warranty.
Why the BMW X4 M40i's Plastic Housing Fails
Affected Vehicles
BMW X4 M40i (B58B30, 2018-2024)
Typical Failure Mileage
50,000-80,000 miles
Root Cause
The B58's plastic oil filter housing can become brittle with age and heat cycling, leading to cracking and oil or coolant leaks. The cartridge-style filter design and overtightening of the filter cap during oil changes accelerate the problem .
Why It Happens
The B58's plastic oil filter housing can become brittle with age and heat cycling, leading to cracking and oil or coolant leaks. The cartridge-style filter design and overtightening of the filter cap during oil changes accelerate the problem .
Dealer (parts + labour)
£1,800-£3,000
Specialist (parts + labour)
£900-£1,500
What it involves
Replace plastic housing with updated unit, new gaskets, oil change
Suitability
80,000+ miles; permanent fix with revised part
1 - 2 daysDealer (parts + labour)
£9,000-£14,000
Specialist (parts + labour)
£4,500-£8,500
What it involves
Supply & fit rebuilt B58 with upgraded housing and cooling components
Suitability
If housing failure caused engine damage or high mileage rebuild justified
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Oil Filter Housing Replacement Minor | £1,800-£3,000 | £900-£1,500 | Replace plastic housing with updated unit, new gaskets, oil change | 80,000+ miles; permanent fix with revised part | 1 - 2 days |
 Full Replacement - rebuilt engine Best Value | £9,000-£14,000 | £4,500-£8,500 | Supply & fit rebuilt B58 with upgraded housing and cooling components | If housing failure caused engine damage or high mileage rebuild justified | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical BMW X4 M40i (2018-2024) retains strong value, with examples ranging from £18,000-£45,000 depending on mileage and condition. Replacement cost is typically small relative to vehicle value; well-maintained M40is justify rebuilt engine investment.
Our Recommendation
Our Recommendation
Oil filter housing replacement at a specialist is far cheaper than dealer pricing and addresses the issue permanently with updated parts. If caught early, there's no need to replace the whole engine. However, if the housing failure has caused oil starvation and bearing damage, a full rebuilt engine with upgraded components is the only safe route.
Don't Let Engine Failure Write Off Your BMW X4 M40i
From oil filter housing leaks to coolant system failures and PCV valve issues, B58 engines in the X4 M40i have specific weak points that can lead to costly repairs. EnginesMarket connects you with trusted UK BMW specialists who supply rebuilt B58 engines with upgraded components designed to address these original failure points - all backed by a minimum 12-month unlimited-mileage warranty. Compare prices across our nationwide network and get back on the road without the main dealer premium.
Compare rebuilt B58 BMW X4 M40i engine prices
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific BMW X4 M40i. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier.
BMW X4 M40i Engine ReplacementFrequently Asked Questions
Question 1How much does a BMW X4 M40i engine replacement cost in the UK-
A rebuilt B58 engine for the BMW X4 M40i typically costs £4,500-£8,500 supply-only, depending on the exact B58 variant and specification. Specialist fitting adds £650-£910 (10-14 hours labour at independent rates). Main dealer replacement can be significantly higher - often £9,000+ for a new engine.
- Rebuilt B58 supply-only: £4,500-£8,500
- Used B58: £2,000-£3,800
- Specialist fitting: £650-£910
Question 2Is the BMW X4 M40i B58 engine reliable for high mileage-
The B58 is widely considered BMW's most reliable modern six-cylinder petrol engine. With proper maintenance, it routinely exceeds 150,000-200,000 miles without major failures .
- Closed-deck block design provides exceptional strength
- Common minor issues: oil filter housing leaks, coolant cap failure, PCV valve
- Well-maintained B58 engines last 300,000+ km before major work is needed
Question 3What are the signs of B58 oil filter housing failure in an X4 M40i-
The plastic oil filter housing in the B58 can become brittle and develop cracks, leading to oil or coolant leaks. Look for oil spots under the car, low oil levels between services, or coolant loss without visible external leaks .
- Average lifespan of the plastic housing: approximately 8 years
- Housing replacement at a specialist: £900-£1,500
- Ignoring the leak can lead to oil starvation and engine damage
Question 4Is it worth replacing the engine on a high-mileage BMW X4 M40i-
Yes, if the body and transmission are sound. A £4,500-£8,500 rebuilt B58 engine can add 100,000+ miles to a well-maintained X4 M40i - far cheaper than replacing the whole vehicle, which typically retains strong value at £18,000+.
- A 2018 X4 M40i with 100k miles is worth £15,000-£22,000 - replacement makes financial sense
- Rebuilt B58 includes upgraded components addressing original failure points
- Compare to buying another used M40i with unknown engine history
- Typical rebuilt B58 lifespan: 100,000+ miles with proper maintenance
Question 5Does BMW X4 M40i engine replacement include ISN coding and ECU matching-
Professional replacement includes ISN (Individual Serial Number) coding to match the replacement engine to your X4 M40i's immobiliser and ECU. Never skip this step.
- ISN coding ensures the engine starts and runs with your car's security system
- Without correct coding, the immobiliser will prevent engine operation
- All EnginesMarket specialists include ISN matching and DDE calibration
- The 48V MHT system (2021+) also requires hybrid system recalibration
Question 6What's the difference between the X4 M40i and X4 M40i MHT engines-
The X4 M40i MHT (2021-2024) adds a 48V mild hybrid system with an 11hp electric boost and coasting functionality. The base B58 engine remains fundamentally the same, but the MHT system adds complexity.
- MHT adds 11hp electric assistance under acceleration
- MHT enables engine-off coasting for improved fuel economy
- MHT components (starter-generator, 48V battery) are BMW-specific
- MHT engine replacement requires professional 48V system isolation
Why Choose UsCompare BMW X4 M40iEngine PricesToday
100+ B58 engines supplied through our network
12-Month Warranty on every rebuilt X4 M40i engine
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