Mercedes-Benz ML , R , GL Class - Replace Serpentine Belt

ESTIMATED TIME 30 min

DIY COST $15-$30

DIFFICULTY Very Easy

Symptoms

Common symptoms of a bad serpentine belt include:

Squealing noise when the engine is on.
The check battery light is on.
Insufficient AC cooling during traffic.

What will you need?

Parts

Mercedes-Benz Serpentine Belt

Tools

17mm deep socket
Socket handle

Procedure

Park the vehicle on level ground, set the parking brakes, and allow the engine to cool down.
Draw a layout of your serpentine belt's original routing or at a minimum take a picture so that when you install the new belt you will know how to route it.
Insert the 17mm socket into the tensioner bolt.
Put on the socket handle on the socket and turn counterclockwise to loosen the belt tensioner. The tensioner should move upwards.
Slide the belt off the idle pulley on top or any pulley that you find easy.
Remove the belt from all the pulley and discard.
Inspect the new serpentine belt. Position the new serpentine belt as per the drawn layout. Make sure your pulley is seated properly on all the pulleys.
Using a 17mm socket and a handle, turn the tensioner bolt counterclockwise, the same way you did to release the belt.
Slide the belt over the tensioner pulley. Slowly release the tensioner. If you are not able to slide the belt over the tensioner pulley because the belt seems too short, there is a good chance that the belt is not seated properly on one of the pulleys.
Inspect telt position at each pulley.
Start the engine and inspect.

Frequently Asked Question

How do you know if your serpentine belt is bad?

One of the common symptoms of a defective serpentine belt is a squealing noise when the engine is on. Since the serpentine belt drives the alternator, coolant pump, and AC compressor, you may experience low alternator output, low AC cooling efficiency, and higher engine temperature.

Can you drive a Mercedes-Benz with a bad serpentine belt?

It is not recommended to drive with a bad serpentine belt. If the serpentine belt fails, power steering will get hard and the alternator will not charge the battery leading to the engine dying while driving.