How much does a BMW Z4 M40i engine replacement cost in the UK-

A BMW Z4 M40i engine replacement typically costs £3,500-£7,500 supply-only for rebuilt units, or £5,500-£10,500 fitted by a specialist. Used B58B30 engines: £2,500-£4,500 supply-only. Reconditioned units: £4,200-£6,500 supply-only. Rebuilt units with warranty: £5,500-£8,500 supply-only. Professional fitting adds £1,000-£2,000 depending on workshop location. LCI B58B30M2 units command premium pricing: £3,500-£5,500 used.

Is the BMW Z4 M40i B58 engine reliable-

The B58 is widely regarded as one of BMW's most reliable modern turbo engines. However, it has known weaknesses that typically appear between 50,000-100,000 miles. PCV diaphragm failure integrated into valve cover - replace with upgraded unit. Electric water pump failure - replace preventatively at 60k miles. Charge pipe cracking on track cars - upgrade to aluminium. Regular oil changes with BMW LL-01 approved oil are essential. Many owners report 100,000+ miles with no major issues.

What are the signs of PCV failure in a BMW Z4 M40i-

The most common symptoms are a whistling noise from the engine bay, excessive oil consumption (1L per 1,000 miles or more), rough idle, and visible oil leaks around the valve cover. Whistling noise that changes with engine RPM. Oil consumption increasing noticeably. Blue smoke on start-up. PCV failure can lead to oil seal failure if left unchecked. Specialist valve cover replacement costs £700-£1,200.

What are the signs of water pump failure in a BMW Z4 M40i-

The B58's electric water pump can fail suddenly with little warning. Overheating within a mile of failure. Coolant loss without visible external leaks. Warning lights on the dashboard. Electric water pump failure is more common than mechanical pump failure on B58 engines. Proactive replacement at 60k-70k miles is strongly recommended.

Is it worth replacing the engine on a high-mileage BMW Z4 M40i-

For a Z4 M40i worth £30,000-£50,000, a rebuilt B58 at £5,500-£8,500 can make financial sense if the body, interior, and chassis are in good condition. Compare replacement cost against vehicle value - replacement is viable up to 70% of car's value. Low-mileage M40i examples command strong money (£30k-£40k). B58 is a robust engine - replacement restores factory performance. Always factor 12-month warranty into replacement decision.

What's the difference between the Z4 M40i and the Z4 sDrive30i-

The key differences between the Z4 M40i and sDrive30i are significant: M40i uses turbocharged B58B30, 340-382hp - performance flagship. sDrive30i uses naturally aspirated N52B30, 258hp - more economical. M40i replacement costs significantly more (£5,500-£8,500 vs £2,400-£3,800 for N52). M40i offers 0-62mph in 4.5 seconds vs 5.5+ seconds for 30i. M40i is the choice for performance enthusiasts.

BMW Z4 M40i SPECIALISTS

BMW Z4 M40i Engine Replacement Compare Prices & Get Quotes

Get quotes today from trusted UK BMW Z4 M40i engine specialists. Compare prices on reconditioned, rebuilt and used B58 turbo straight-six engines for the G29 roadster - supply & fit available nationwide.

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

100+ Suppliers

BMW Z4 M40i Engine

from£3,500 to £7,500

Usedfrom £2,500
Reconditionedfrom £4,200
Common codesB58B30, B58B30M1, B58B30M2

Bmw z4Used Engine — B58B30

Bmw z4 M40i Reconditioned Engine — B58B30

Bmw z4Reconditioned Engine — B58B30

Bmw z4Rebuilt Engine — B58B30

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide NetworkInstant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide NetworkInstant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide NetworkInstant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

How it works

3 Simple Steps to Finding the Right Replacement Engine

Clear information first, then the right engine and specialist for your exact vehicle.

Variant History

BMW Z4 M40i Engine History & Specs at a Glance

The BMW Z4 M40i is the flagship performance variant of the G29 Z4, launched in 2019 as the spiritual successor to the Z4M. Powered exclusively by BMW's acclaimed B58B30 3.0-litre turbocharged straight-six, it delivers 340hp in standard form and up to 382hp in later LCI variants. The B58 - widely regarded as one of BMW's most reliable modern engines - combines closed-deck construction, integrated exhaust manifold, and TwinPower turbo technology for effortless performance.

2019
G29 Z4 M40i launched with B58B30, 340hp, 500Nm, 8-speed automatic
2020
B58B30M1 engine code introduced; power unchanged
2022
Minor ECU updates for improved response
2023
LCI facelift: B58B30M2 with 382hp, 6-speed manual option introduced
2024
present - B58B30M2 continues with 382hp, 8-speed auto and 6-speed manual options

Every engine fitted to the BMW Z4 M40i is covered below, with UK rebuilt pricing and known failure points specific to the B58 turbo straight-six.

Engine Codes & Pricing

BMW Z4 M40i Engine Codes Specifications & Replacement Cost

Find your exact engine code, specs and UK replacement cost guide.

B58B30 — 3.0L Twin-Turbo Straight-Six Petrol (2019-2020)

Power Output: 340hp (250kW) @ 5,000-6,500rpm
Torque: 500Nm @ 1,600-4,500rpm
Displacement: 2,998cc
Years Fitted: 2019-2020 (G29 Z4 M40i)
Engine Features: Closed-deck aluminium block, integrated exhaust manifold, TwinPower twin-scroll turbo, direct injection

Can’t find your exact engine code?-> Get quotes for B58B30 BMW Z4 M40i engine replacement

-> Get quotes for B58B30 BMW Z4 M40i engine replacement

Common Problems

BMW Z4 M40i Engine Problems Repair Cost vs Replacement

The BMW Z4 M40i's B58 turbo straight-six is widely regarded as one of BMW's most reliable modern engines, but it's not immune to wear. The most common issues - PCV diaphragm failure, water pump failure, and charge pipe fragility - are well-documented and typically occur between 50,000-80,000 miles. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address these original failure points - plus a minimum 12-month unlimited mileage warranty.

Common failure points and repair options

PCV Diaphragm Failure

Affected: BMW Z4 M40i (G29 2019-present, B58B30, B58B30M1, B58B30M2)
Typical failure mileage: 50,000-75,000 miles (80,000 km)

Root cause

The crankcase ventilation (PCV) system is integrated into the valve cover. The rubber diaphragm tears over time, causing excessive crankcase pressure, whistling noises, oil consumption, and oil leaks.

Repair options

Repair tier	Dealer price	Specialist price
Valve Cover & PCV Replacement	£1,200-£1,800	£700-£1,200
Full Replacement - rebuilt/reconditioned engine	£8,500-£12,000	£5,500-£8,500

Our recommendation

PCV failure on the B58 is a well-understood issue. Specialist valve cover replacement with an upgraded PCV unit costs under £1,200 and resolves the problem permanently. This is almost always the right first step - a full engine replacement is rarely necessary unless the engine has suffered catastrophic failure or exceeded 100,000 miles with multiple other issues.

-> Compare rebuilt B58 engine prices for your BMW Z4 M40i

Electric Water Pump Failure

Affected: BMW Z4 M40i (G29 2019-present, B58B30, B58B30M1, B58B30M2)
Typical failure mileage: 60,000-100,000 miles (100,000-150,000 km)

Root cause

The B58's electric water pump can fail prematurely, leading to overheating and potential engine damage. Symptoms include coolant loss, rising temperature gauge, and warning lights.

Repair options

Repair tier	Dealer price	Specialist price
Preventative - Water Pump & Thermostat Replacement	£800-£1,200	£500-£800
Full Replacement - rebuilt/reconditioned engine	£8,500-£12,000	£5,500-£8,500

Our recommendation

On any B58-powered Z4 M40i approaching 60,000 miles, proactive electric water pump replacement is the single best investment you can make. A £500-£800 specialist preventative replacement is far cheaper than a warped cylinder head or full engine replacement.

-> Get quotes for BMW Z4 M40i water pump replacement and rebuilt engines

Charge Pipe Cracking

Affected: BMW Z4 M40i (G29 2019-present, B58B30, B58B30M1, B58B30M2)
Typical failure mileage: 30,000-60,000 miles (sooner on track cars)

Root cause

The B58's factory charge pipe is made of plastic that can crack under boost pressure, especially during track use or spirited driving. Symptoms include loss of power, boost leaks, and potentially limp mode.

Repair options

Repair tier	Dealer price	Specialist price
Charge Pipe Replacement (OEM)	£600-£900	£400-£650
Charge Pipe Replacement (Aftermarket Upgrade)	£700-£1,100	£500-£800
Full Replacement - rebuilt/reconditioned engine	£8,500-£12,000	£5,500-£8,500

Our recommendation

On any Z4 M40i that sees track use or aggressive driving, an aftermarket aluminium charge pipe is a worthwhile upgrade. At £500-£800 fitted, it's cheap insurance against a boost leak that could strand you on track.

-> Compare BMW Z4 M40i charge pipe and engine replacement costs

Don't Let Engine Failure Write Off Your BMW Z4 M40i

A failed B58 doesn't have to mean the end of the road for your Z4 M40i. Whether you're facing PCV failure, water pump failure, or charge pipe issues, EnginesMarket connects you with trusted UK BMW turbo specialists who supply rebuilt engines with upgraded components specifically designed to address the original failure points. Every engine comes with a minimum 12-month unlimited mileage warranty, nationwide delivery, and supply & fit options across the UK. Compare prices today - and keep one of BMW's most thrilling roadsters on the road without paying the main dealer premium.

Compare BMW Z4 M40i Engine Replacement Prices Now ->

FAQ

BMW Z4 M40i Engine ReplacementFrequently Asked Questions

Everything BMW Z4 M40i owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.

A BMW Z4 M40i engine replacement typically costs £3,500-£7,500 supply-only for rebuilt units, or £5,500-£10,500 fitted by a specialist.

Used B58B30 engines: £2,500-£4,500 supply-only
Reconditioned units: £4,200-£6,500 supply-only
Rebuilt units with warranty: £5,500-£8,500 supply-only
Professional fitting adds £1,000-£2,000 depending on workshop location
LCI B58B30M2 units command premium pricing: £3,500-£5,500 used

-> Compare BMW Z4 M40i engine replacement prices from UK specialists

The B58 is widely regarded as one of BMW's most reliable modern turbo engines. However, it has known weaknesses that typically appear between 50,000-100,000 miles.

PCV diaphragm failure integrated into valve cover - replace with upgraded unit
Electric water pump failure - replace preventatively at 60k miles
Charge pipe cracking on track cars - upgrade to aluminium
Regular oil changes with BMW LL-01 approved oil are essential
Many owners report 100,000+ miles with no major issues

-> Get quotes for BMW Z4 M40i B58 engine repairs

The most common symptoms are a whistling noise from the engine bay, excessive oil consumption (1L per 1,000 miles or more), rough idle, and visible oil leaks around the valve cover.

Whistling noise that changes with engine RPM
Oil consumption increasing noticeably
Blue smoke on start-up
PCV failure can lead to oil seal failure if left unchecked
Specialist valve cover replacement costs £700-£1,200

-> Get quotes for BMW Z4 M40i PCV repair

For a Z4 M40i worth £30,000-£50,000, a rebuilt B58 at £5,500-£8,500 can make financial sense if the body, interior, and chassis are in good condition.

Compare replacement cost against vehicle value - replacement is viable up to 70% of car's value
Low-mileage M40i examples command strong money (£30k-£40k)
B58 is a robust engine - replacement restores factory performance
Always factor 12-month warranty into replacement decision

-> Check BMW Z4 M40i engine replacement value for your specific car

The key differences between the Z4 M40i and sDrive30i are significant:

M40i uses turbocharged B58B30, 340-382hp - performance flagship
sDrive30i uses naturally aspirated N52B30, 258hp - more economical
M40i replacement costs significantly more (£5,500-£8,500 vs £2,400-£3,800 for N52)
M40i offers 0-62mph in 4.5 seconds vs 5.5+ seconds for 30i
M40i is the choice for performance enthusiasts

-> Compare BMW Z4 M40i and sDrive30i engine replacement options

Why Choose Us

Compare BMW Z4 M40i Engine Prices Today

Comparing quotes for your BMW Z4 M40i is free, no-obligation, and specific to your exact G29 roadster and its engine code - B58B30, B58B30M1, or B58B30M2. Whether you need a used replacement, a reconditioned unit, or a full rebuilt engine with upgraded components, our network of trusted UK BMW turbo specialists delivers transparent pricing and nationwide coverage. Don't let a failed engine end the life of BMW's most thrilling roadster - compare prices today and get back on the road with confidence.

11,000+11,000+ BMW Z4 engines supported through our network, including M40i variants

12-Month12-Month Warranty on every rebuilt B58B30 engine

NationwideNationwide UK delivery

Get Free BMW Z4 M40i Engine Quotes ->

Compare quotes from trusted UK BMW Z4 M40i engine specialists with warranty-backed rebuilt, reconditioned and used options nationwide.

BMW Z4 M40i Engine Replacement Compare Prices & Get Quotes

Get your free Bmw z4 M40i engine quotes

3 Simple Steps to Finding the Right Replacement Engine

BMW Z4 M40i Engine History & Specs at a Glance

BMW Z4 M40i Engine Codes Specifications & Replacement Cost

B58B30 — 3.0L Twin-Turbo Straight-Six Petrol (2019-2020)

BMW Z4 M40i Engine Problems Repair Cost vs Replacement

PCV Diaphragm Failure

Electric Water Pump Failure

Charge Pipe Cracking

Don't Let Engine Failure Write Off Your BMW Z4 M40i

BMW Z4 M40i Engine ReplacementFrequently Asked Questions

Compare BMW Z4 M40i Engine Prices Today