BMW X7 40i Engine ReplacementCompare Prices & Get Quotes

A BMW X7 40i engine replacement typically costs £3,500-£5,800 supply-only for a reconditioned B58, or £4,200-£6,200 for a rebuilt unit. Fitted by a specialist, expect £5,500-£8,500 total.

• B58B30C (2019-2022) reconditioned: £3,500-£5,000 supply-only
• B58B30M1 (2022-2023) reconditioned: £3,800-£5,200 supply-only
• B58B30M2/B58B30P (2023+) reconditioned: £4,000-£5,500 supply-only
• Professional fitting adds £1,500-£2,500 depending on your location and workshop

VANOS failure in the X7 40i's B58 engine typically presents as rough idle, reduced power, poor fuel economy, and check engine lights with P0011/P0012 codes.

• Rough idle and hesitation on acceleration are early symptoms
• P0011/P0012 codes indicate camshaft timing deviation from specification
• The most common cause is O-ring degradation in the VANOS solenoids
• If ignored, prolonged oil pressure loss can damage cam lobes irreversibly
• Solenoid replacement costs £550-£950 at a specialist if caught early

Early BMW X7 40i B58B30C engines (2019-2022) can experience timing chain tensioner wear between 60,000-90,000 miles. The plastic tensioner components degrade under thermal cycling, allowing chain slack.

• Listen for rattling at cold start - this signals imminent tensioner failure
• Proactive tensioner replacement costs £800-£1,200 at specialist workshops
• The updated B58TU (B58D) chain tensioner design addresses the original weakness
• Catastrophic failure causes valve damage requiring full engine replacement

For a G07 X7 40i worth £35,000-£60,000, engine replacement (£4,200-£6,200 supply-only) typically represents 10-15% of the vehicle's value - making it a financially viable option for most owners.

• Compare replacement cost against vehicle value - replacement is viable up to roughly 60-70% of the car's value
• Given the high vehicle value, replacement is usually justified if the body and interior are in excellent condition
• Low-mileage, well-serviced, or cherished 40i examples justify the investment
• Always factor the 12-month warranty into your decision

The B58B30C (2019-2022) is the initial G07 X7 40i engine producing 340hp. The B58B30M1 (2022-2023) is the LCI update with 48V mild-hybrid and 340hp. The B58B30M2 (2023+) introduced increased output of 375-381hp with MHEV. The B58B30P (2023+) is the latest LCI engine code producing 381hp with 48V MHEV.

• B58B30C: 340hp, no mild-hybrid (pre-LCI)
• B58B30M1: 340hp with 48V MHEV (early LCI)
• B58B30M2: 375-381hp with 48V MHEV (later LCI)
• B58B30P: 381hp with 48V MHEV (latest LCI)
• All are 3.0L (2998cc) straight-six turbo petrol engines

Swapping a 40i's B58 petrol for a diesel (xDrive30d/40d B57) is technically complex and rarely cost-effective. The engines have different mounts, wiring looms, ECUs, cooling systems, and fuel systems.

• B58 is a 3.0L petrol; B57 is a 3.0L diesel - fuel system, ECU and exhaust are completely different
• LCI models with MHEV systems add further complexity
• Transmission may also differ - petrol and diesel X7s use different gearbox calibrations
• Insurance must be notified of any non-standard engine swap
• Stick to like-for-like code-matching for warranty coverage and straightforward installation