Engines Market

BMW X3 M40i SPECIALISTS

BMW X3 M40i Engine Replacement Compare Prices & Get Quotes

Get quotes today from trusted UK BMW X3 M40i engine specialists. Compare prices on reconditioned, rebuilt and used B58 engines for your M40i - supply and fit available across the UK.

Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
BMW X3 M40i Engine
from£4,000 to £7,000
  • Usedfrom £3,500
  • Reconditionedfrom £4,000
  • Common codesB58B30, B58B30O1
BMW x3 M40i Used Engine — B58B30BMW x3Used Engine — B58B30BMW x3 M40i Reconditioned Engine — B58B30BMW x3Reconditioned Engine — B58B30BMW x3 M40i Rebuilt Engine — B58B30BMW x3Rebuilt Engine — B58B30

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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 X3 M40i Engine History & Specs at a Glance

The BMW X3 M40i joined the G01 generation as the performance flagship petrol model, powered by the legendary B58 straight-six engine. Over the G01 production run, the M40i badge carried the B58B30 engine with two distinct power outputs - the earlier 355hp and the later 382hp version with 48V mild hybrid assistance.

BMW X3 M40i
  1. 2018

    G01 X3 M40i debuts with B58B30, 3.0-litre straight-six petrol, 355hp, 500Nm torque, all-wheel drive

  2. 2019

    Minor ECU calibration update; no power change

  3. 2020

    B58B30 receives power increase to 382hp, 500Nm torque

  4. 2020

    48V mild hybrid starter-generator introduced on some markets

  5. 2022

    G01 LCI facelift; M40i continues with B58B30O1, 382hp, 48V MHEV

  6. 2024

    G01 production ends; G45 X3 M50 replaces M40i with 393hp B58B30M2

Every engine fitted to the BMW X3 M40i is covered below, with UK rebuilt pricing and known failure points.

Engine Codes & Pricing

BMW X3 M40i Engine Codes Specifications & Replacement Cost

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

B58B30 — 3.0 Petrol (2018-2020) engine

B58B30 — 3.0 Petrol (2018-2020)

Power Output
355hp, 500Nm torque
Years Fitted
2018-2020

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Common Problems

BMW X3 M40i Engine Problems Repair Cost vs Replacement

The BMW X3 M40i is powered by the B58B30 straight-six turbo petrol - widely regarded as one of BMW's best modern engines. With a closed-deck block, forged internals, and twin-scroll turbo technology, the B58 delivers effortless power and exceptional refinement. However, coolant transfer pipe failure, PCV system issues, and oil leaks are the most common failure points. Every rebuilt engine supplied through EnginesMarket includes upgraded components addressing the original failure point, plus a minimum 12-month unlimited-mileage warranty.

Common failure points and repair options

Coolant Transfer Pipe Failure

Affected
BMW X3 M40i (B58B30, 2018-2024)
Typical failure mileage
30,000-70,000 miles
Root cause
The factory plastic coolant transfer pipe at the front of the B58 engine becomes brittle under repeated thermal cycling, developing cracks that cause sudden and rapid coolant loss. The engine management system reduces power, but continued driving causes overheating and head gasket failure.

Repair options

Repair tierDealer priceSpecialist price
Coolant transfer pipe replacement£1,200-£1,800£700-£1,100
Pipe + head gasket£3,500-£5,000£2,200-£3,500
Full Replacement - rebuilt/reconditioned engine£7,000-£10,000£5,000-£7,500
Our recommendation
B58 coolant leaks are the single most discussed issue on X3 M40i forums. If you smell coolant or see the low coolant warning, act immediately. The preventative pipe replacement costs £700-£1,100 at a specialist - a small price on a £25,000+ car. Ignore it, and a £5,000-£7,500 rebuilt engine becomes the only fix. Check your coolant level monthly.
-> Compare rebuilt B58B30 BMW X3 M40i engine prices

PCV System Failure

Affected
BMW X3 M40i (B58B30, 2018-2024)
Typical failure mileage
60,000-100,000 miles
Root cause
The PCV (Positive Crankcase Ventilation) diaphragm can fail, causing excessive crankcase pressure, oil consumption, and rough idle. In severe cases, it can lead to oil seal failure and increased oil consumption.

Repair options

Repair tierDealer priceSpecialist price
PCV diaphragm replacement£500-£800£300-£500
Full Replacement - rebuilt/reconditioned engine£7,000-£10,000£5,000-£7,500
Our recommendation
PCV failure is common on higher-mileage B58 engines. A £300-£500 repair at a specialist is far cheaper than a full engine rebuild. However, if excessive oil consumption has caused bearing damage, a rebuilt engine may be necessary.
-> Compare rebuilt B58B30 BMW X3 M40i engine prices

Oil Leaks

Affected
BMW X3 M40i (B58B30, 2018-2024)
Typical failure mileage
50,000-90,000 miles
Root cause
Oil leaks can occur from the oil filter housing gasket, valve cover gasket, and other seals as they degrade over time due to heat cycling.

Repair options

Repair tierDealer priceSpecialist price
Gasket replacement£500-£900£300-£600
Full Replacement - rebuilt/reconditioned engine£7,000-£10,000£5,000-£7,500
Our recommendation
Oil leaks on the B58 are usually manageable. A £300-£600 gasket replacement at a specialist is far cheaper than a full engine rebuild. However, if oil loss has been severe enough to cause bearing damage (indicated by knocking or low oil pressure), a rebuilt engine may be the only safe path.
-> Compare rebuilt B58B30 BMW X3 M40i engine prices

Don't Let Engine Failure Write Off Your BMW X3 M40i

The B58-powered BMW X3 M40i is one of the most desirable performance SUVs on the market, but its cooling system, PCV system, and oil seals require vigilance. Early detection of coolant loss, rough idle, or oil leaks can save the engine. Every rebuilt engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty, with upgraded components addressing the original failure points. Compare quotes from UK specialists today.

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FAQ

BMW X3 M40i Engine ReplacementFrequently Asked Questions

Everything BMW X3 M40i owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.

Why Choose Us

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Comparing quotes for your BMW X3 M40i engine replacement is free, no-obligation, and specific to your exact vehicle and engine code. Enter your registration above to connect with vetted UK specialists who stock the right B58 engine for your M40i - whether you need a used unit, a reconditioned replacement, or a fully rebuilt engine with warranty.

150+150+ BMW X3 M40i engines supplied through our network
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