⚙️Serpentine Belt
BMW 1 Series Serpentine Belt
Find serpentine belt routing diagrams, part numbers, and replacement instructions for your BMW 1 Series. All years covered.
Quick Answer
The BMW 1 Series serpentine belt routes around the alternator, power steering pump, A/C compressor, and water pump. Belt length and routing vary by engine — see diagrams below.
2019-2024
2019-2024Belt TypeMulti-rib serpentine (6PK or 7PK)
Belt Length85" - 100" (varies by engine and A/C option)
Tensioner TypeAutomatic spring-loaded tensioner
Replacement Interval60,000 - 100,000 miles
Notes
- →Take a photo of the belt routing BEFORE removing the old belt
- →Use a 1/2" breaker bar or 15mm socket to release the automatic tensioner
- →Inspect the tensioner pulley and idler pulleys for bearing noise while the belt is off
- →A new belt may squeal briefly at startup — this usually stops within a few minutes
2013-2018
2013-2018Belt TypeMulti-rib serpentine (6PK or 7PK)
Belt Length85" - 100" (varies by engine and A/C option)
Tensioner TypeAutomatic spring-loaded tensioner
Replacement Interval60,000 - 100,000 miles
Notes
- →Take a photo of the belt routing BEFORE removing the old belt
- →Use a 1/2" breaker bar or 15mm socket to release the automatic tensioner
- →Inspect the tensioner pulley and idler pulleys for bearing noise while the belt is off
- →A new belt may squeal briefly at startup — this usually stops within a few minutes
2007-2012
2007-2012Belt TypeMulti-rib serpentine (6PK or 7PK)
Belt Length85" - 100" (varies by engine and A/C option)
Tensioner TypeAutomatic spring-loaded tensioner
Replacement Interval60,000 - 100,000 miles
Notes
- →Take a photo of the belt routing BEFORE removing the old belt
- →Use a 1/2" breaker bar or 15mm socket to release the automatic tensioner
- →Inspect the tensioner pulley and idler pulleys for bearing noise while the belt is off
- →A new belt may squeal briefly at startup — this usually stops within a few minutes
2004-2006
2004-2006Belt TypeMulti-rib serpentine (6PK or 7PK)
Belt Length85" - 100" (varies by engine and A/C option)
Tensioner TypeAutomatic spring-loaded tensioner
Replacement Interval60,000 - 100,000 miles
Notes
- →Take a photo of the belt routing BEFORE removing the old belt
- →Use a 1/2" breaker bar or 15mm socket to release the automatic tensioner
- →Inspect the tensioner pulley and idler pulleys for bearing noise while the belt is off
- →A new belt may squeal briefly at startup — this usually stops within a few minutes
Frequently Asked Questions
- How do I replace the serpentine belt on a BMW 1 Series?
- Release tension on the automatic tensioner with a breaker bar, slide the old belt off, route the new belt per the diagram (usually on a sticker under the hood), and release the tensioner onto the new belt. The job takes 15-30 minutes.
- How do I know if my BMW 1 Series serpentine belt needs replacing?
- Signs include squealing at startup, visible cracks or fraying on the belt, loss of power steering or A/C, and the battery light coming on. Most belts should be replaced every 60,000-100,000 miles.
- What happens if the serpentine belt breaks on my BMW 1 Series?
- If the serpentine belt breaks, you lose power steering, alternator charging, A/C, and (on some engines) the water pump. Pull over immediately — driving without the water pump will cause overheating and engine damage.
- Where is the belt routing diagram on a BMW 1 Series?
- Most BMW 1 Series models have a belt routing diagram on a sticker under the hood, near the radiator support or on the inner fender. If it's missing, check the service manual or see the diagrams below.