Mercedes-Benz S420 Serpentine/Drive Belt Replacement at your home or office.

Our mobile mechanics offer services 7 days a week. Upfront and transparent pricing.

Estimate price near me

Service Location

Customer Ratings

(13)

Included for free with this service

Online Booking

Mechanic comes to you

12-month / 12k-mile warranty

Free 50 point safety inspection

Our certified mobile mechanics can come to your home or office 7 days a week between 7 AM and 9 PM.

Customer Ratings

(13)

Serpentine/Drive Belt Replacement Service

How much does a Serpentine/Drive Belt Replacement cost?

On average, the cost for a Mercedes-Benz S420 Serpentine/Drive Belt Replacement is $153 with $58 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1999 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$240.57Shop/Dealer Price$289.47 - $396.78
1995 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$210.51Shop/Dealer Price$256.92 - $356.71
1996 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$220.57Shop/Dealer Price$269.50 - $376.83
1998 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$220.57Shop/Dealer Price$269.46 - $376.76
1997 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$220.57Shop/Dealer Price$269.52 - $376.88
1994 Mercedes-Benz S420V8-4.2LService typeSerpentine/Drive Belt ReplacementEstimate$230.07Shop/Dealer Price$280.75 - $389.40
Show example Mercedes-Benz S420 Serpentine/Drive Belt Replacement prices

What is a serpentine belt and how does it work?

A serpentine belt is a relatively long, flat, multi-ribbed belt that is driven by the engine’s crankshaft pulley. The belt drives many, and often all, of the engine accessories such as the alternator, air conditioning compressor, power steering pump, water pump, and air pump. The serpentine belt is tensioned by a hydraulic or spring-loaded automatic tensioner. Some older cars use a serpentine belt to drive most accessories but will also have a shorter v-style belt to drive, for example, the power steering pump.

Belts

When to consider replacing the serpentine belt:

  • Regularly scheduled maintenance. Typically, belt manufacturers recommend belt replacement at 90,000 miles. However, the belt must be inspected for wear or damage at regular intervals prior to this high mileage.
  • Squealing noise, belt slippage, visible belt damage. Should the belt fail or wear out prematurely, you may hear noise or you may see visible signs of deterioration such as missing chunks of rubber, excessive cracking, or a shredded appearance on the edge of the belt.
  • Battery Light. A loose belt, perhaps caused by a defective tensioner, may not drive the alternator at adequate speed and thus the battery may discharge, causing the warning light to illuminate.
  • Engine overheating. Often, the serpentine belt drives the water pump. In those applications, if the belt breaks the engine will overheat in seconds to minutes. If the belt is inadequately tensioned, you may notice higher-than-normal engine operating temperature.

How do mechanics replace the serpentine belt?

  • Prior to removing the belt, the mechanic must run the engine to determine if the idler pulley and the belt tensioner are noise-free. Those rotating components have grease filled bearings and are subject to wear. In addition, the mechanic will ensure that all pulleys and accessories are turning in the same plane. These steps help make sure your new belt will operate trouble-free for its full-service life.
  • The belt’s routing path through the various components is noted. The belt tensioner is released, usually with a wrench or lever, to release the tension from the belt. With the tension off, the belt slides off the pulleys.
  • All rotating components — that is the alternator, air conditioner compressor, etc. — are checked for smooth operation and no noise.
  • If everything checks out, the new belt is slipped over all of the pulleys while holding the tensioner away from the belt. Once the belt is centered on all pulleys, the tensioner is released and the installation is complete. The engine is run to ensure normal operation.

Is it safe to drive with a serpentine belt problem?

No. Should the belt have visible damage, you risk unexpected and sudden breakage that could potentially leave you stranded. Serpentine belt problems that result in the alternator not charging may cause the battery to discharge, which will result in loss of electrical power to the vehicle. Additionally, if a deteriorated belt breaks and that belt drives the water pump, the engine will overheat in a matter of seconds.

When replacing the serpentine belt keep in mind:

  • On many cars, the expected service life of a serpentine belt is around 90,000 miles. Should the belt fail well prior to that, a very careful inspection should be performed to check for out-of-alignment pulleys, a possibly out-of-position crankshaft harmonic balancer on which the drive pulley is mounted, binding pulleys, or a defective belt tensioner.
  • Attention should always be given to serpentine belt routing, since proper routing is critical to proper belt tension, and function of the driven components.
  • Sometimes it is difficult to distinguish serpentine belt related noise from other engine noises. In these cases, a mechanic will determine the origin of the noise by momentarily running the engine without the serpentine belt attached.

Fast and easy service at your home or office

Backed by 12-month, 12.000-mile guarantee


Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Excellent Rating

(13)

Rating Summary
12
0
1
0
0
12
0
1
0
0

Jamie

22 years of experience
91 reviews
Jamie
22 years of experience
Mercedes-Benz S420 V8-4.2L - Serpentine/Drive Belt Replacement - Ontario, California
Great job

Eric

15 years of experience
133 reviews
Eric
15 years of experience
Mercedes-Benz S420 V8-4.2L - Oil Change - Bowie, Maryland
Kept me informed for his arrival. Was very friendly.

Whitney

39 years of experience
783 reviews
Whitney
39 years of experience
Mercedes-Benz S420 V8-4.2L - Fix a Flat Tire (Plug Holes) - Palo Alto, California
It's great.

Whitney

39 years of experience
783 reviews
Whitney
39 years of experience
Mercedes-Benz S420 V8-4.2L - Brake Pads Replacement (Front, Rear) - Palo Alto, California
He is great.

Excellent Rating

(13)

Rating Summary
12
0
1
0
0
12
0
1
0
0
Number of Mercedes-Benz S420 services completed
143+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercedes-Benz MECHANICS
1100+
experts on our platform

Recent articles & questions

A Buyer’s Guide to the 2012 Hyundai Sonata Hybrid
When When Toyota first introduced the Prius, the idea seemed to be that all hybrids and electric cars had to have their own specific models and that they couldn’t look like normal cars. A lot of consumers weren’t too thrilled...
P0186 OBD-II Trouble Code: Fuel Temperature Sensor "B" Circuit Range/Performance
P0186 P0186 trouble code definition Fuel Temperature Sensor "B" Circuit Range/Performance What the P0186 code means P0186 is a generic OBD-II code that is triggered when the fuel temperature sensor B circuit goes out of range during self testing; the...
P0596 OBD-II Trouble Code: Cruise Control Servo Control Circuit High
P0596 means there is an issue with the cruise control servo control circuit. This can be caused by a faulty unit, blown fuses, or broken wires.

Spike in costs around 120,000 miles?

Hi there. Your question of what to expect in service costs is difficult to answer. There are variables involved, whether the vehicle was driven hard by the previous owner(s), or whether the vehicle has had maintenance performed at the recommended...

Everything time I slow down it makes clicking noise

What you are describing sounds like a failing CV joint. A CV (Constant Velocity) joint is a shaft that connects the transmission to the wheels, essentially transferring the power from the drive train directly to the wheels. The CV joint...

Truck is showing a 756 code

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com