Is there a squealing noise when your Mercedes-Benz engine is on? Learn how to fix the problem by replacing the serpentine belt of your Mercedes-Benz. This guide provides instructions on replacing the serpentine belt of a Mercedes V6, V8, and V12 Engines.
Repair Time:
The typical time range in hours required to complete this repair.
Repair Cost:
The average repair cost range in USD to complete this repair by either an honest mechanic or as a DIY. Including the cost of parts but not tools.
This indicates how difficult it is for most DIYers and mechanics to perform this repair.
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
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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 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 you find easy.
Remove the belt from all the pulleys and discard it.
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, as you did to release the belt.
Slide the belt over the tensioner pulley. Slowly release the tensioner. If you cannot 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.
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.
How much does it cost to replace a serpentine belt?
If you’re replacing the serpentine belt, the part will cost around $50-100. The labor cost would be around $ 50 – 150.
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.
Applications
Mercedes-Benz vehicles with V6, V8, and V12 engines.
We hope you find the Mercedes-Benz ML, R, GL Class – Replace Serpentine Belt guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.
Written and fact-checked by:
YOUCANIC Techs
YOUCANIC articles are written by authors who collectively have over 60 years of experience in the automotive field and years of hands-on experience on vehicles. These authors are certified ASE G1 Automotive Maintenance engine professionals (the highest level certification for vehicle maintenance and repair). They hold associate’s and bachelor’s degrees, as well as having gone on to further study to receive a master’s and doctorate degrees. These authors collaborate on research, writing, editing, and fact-checking every article to ensure that it is accurate and up to date and delivers the best counsel and information to YOUCANIC readers.
View all postsRush*t Hila is an engineer and ASE certified in G1 Automotive Maintenance
In addition to the belt itself needing to be periodically replaced, the tensioner pulley (and the idler pulley, if there is one) spins on bearings, and over time, they wear out.
Replacing the serpentine belt is as simple as threading it into position, cranking the tensioner and slipping the belt over the tensioner pulley, or nearest pulley up top. Belt tensioners are mostly spring tension. Once installed, the spring retains pressure to the belt.
Labor costs are estimated between $54 and $68 while parts are priced between $43 and $75. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.
Does One of Your Car Belts Need to Be Replaced?6 Common Signs
Squeaking and Squealing Noises. Worn-out serpentine belts tend to produce squeaking and squealing noises because they cannot handle the pulley tension. ...
We suggest technicians change a pulley whenever a timing belt or serpentine belt is changed and vice versa, but there are eight key warning signs to look out for when a pulley goes bad: Rock – Rock the pulley back and forth. There should be no movement or play from side to side.
The average cost for serpentine belt replacement is between $109 and $134. Labor costs are estimated between $57 and $72, while parts range between $52 and $62. Whether you go to the mechanic or do it yourself, replacing a serpentine belt costs $58 to $126.
It's a good idea for customers to replace both the water pump and the timing belt simultaneously so that both parts are brand new and will wear at the same time.
Serpentine belts usually last about 50,000 miles or five years, or in some cases, even up to 100,000 miles. Your belt should be inspected at 50,000 miles, as this is often when you start to see the belt material breaking down.
Your serpentine belt was made to last. Under ideal circ*mstances, your car's serpentine belt should last 60,000–100,000 miles. It's important to replace this belt as part of your vehicle's scheduled maintenance (even if it looks okay) to avoid it breaking while you're on the road.
One of the earliest signs of a failing serpentine belt is a high-pitched squealing or whining noise, especially during engine startup or when turning the steering wheel. This noise is typically caused by the belt slipping on the pulleys due to reduced tension or deterioration.
The Hidden Dangers: Ignoring Signs of Wear and Tear
One of the most significant risks of driving with a worn serpentine belt is the danger of it breaking while you're on the road. If the belt snaps, it will instantly disable essential functions like the power steering, alternator, and air conditioning.
The serpentine belt is a single, continuous belt that drives multiple devices in your engine, such as the alternator, power steering pump, water pump, and air conditioning compressor. If your serpentine belt breaks, all of these systems will shut down and your vehicle will overheat.
Introduction: My name is Terence Hammes MD, I am a inexpensive, energetic, jolly, faithful, cheerful, proud, rich person who loves writing and wants to share my knowledge and understanding with you.
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