Mercedes B-Class Serpentine Belt

Frequently Asked Questions

How do I replace the serpentine belt on a Mercedes B-Class?

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 Mercedes B-Class 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 Mercedes B-Class?

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 Mercedes B-Class?

Most Mercedes B-Class 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.