2018 Bmw X3 M40iSerpentine Belt Diagram & Size

OEM serpentine belt spec from the factory service manual for the 2018-2024 (2018-2024).

Quick Answer

Routing: REPLACING DRIVE BELT FOR ALTERNATOR (X3 4-CYL. MODELS EXCEPT PHEV, 2018-2019) REPLACING DRIVE BELT FOR ALTERNATOR (X3 4-CYL. MODELS EXCEPT PHEV, 2020-2022) REPLACING DRIVE BELT FOR ALTERNATOR (X3 M40I, 2018-2019) REPLACING DRIVE BELT FOR ALTERNATOR (X3 M40I, 2020-2022) REMOVING AND INSTALLING/REPLACING THE DRIVE BELT FOR STARTER MOTOR GENERATOR (X3 M40I, 2020-2022) REMOVING AND INSTALLING/REPLACING DRIVE BELT FOR COOLANT PUMP (X3 XDRIVE 30E PHEV)
Source: Factory service manual β€” 2018 Bmw X3 M40i 2018-2024.

This vehicle's factory manual

2018 Bmw X3 M40i: confirm the engine, trim, or drivetrain to open the available repair and diagnosis sections.

Open this vehicle’s service manual

What You'll Need

These links search Amazon; confirm the belt or pulley against your engine, equipment and VIN before ordering. As an Amazon Associate, we earn from qualifying purchases.

For belt noise, inspect the belt drive and follow the vehicle's service procedure. Belt manufacturer Dayco advises against using belt dressing to solve serpentine-belt problems. Read Dayco's belt-service guidance.

Related for Your 2018 Bmw X3 M40i

Frequently Asked Questions

What size serpentine belt does a 2018 Bmw X3 M40i use?
Refer to the factory service manual for the exact serpentine belt specification for your 2018 Bmw X3 M40i.
How do I know if my Bmw X3 M40i serpentine belt is bad?
Common signs include squealing on startup (especially when cold), visible cracks or fraying on the ribbed side, power steering or A/C failure, and battery warning lights. The factory manual includes inspection criteria and replacement intervals.