A Guide to the Starter for the 2007-2016 Mercedes-Benz S550
If your S550 won't crank, this guide will help you diagnose the problem and choose the right replacement starter.
- Always test your battery before condemning the starter; a weak battery is the most common cause of starting issues on the S550.
- For reliable performance, choose a new starter from an OE supplier like Bosch or Valeo.
- Replacement is a moderately difficult DIY job requiring an E14 Torx socket and safe access to the underside of the vehicle.
- Expect a professional replacement to cost between $570 and $1,050, depending on the parts and labor rates.
Is Your S550 Starter Failing?
A no-start condition in a Mercedes-Benz S550 can be stressful. While several issues can prevent your car from starting, a failing starter has a few distinct symptoms. It's important to distinguish these from a weak or dead battery, which is a very common issue for these cars and should be the first thing you check. The 2007-2013 (W221) models, in particular, have a small, separate starter battery under the hood that can fail and mimic starter problems.
Common Symptoms of a Bad Starter:
- Single, Loud Click: You press the start button, and instead of the engine cranking, you hear one loud click from the engine bay. This is often the starter's solenoid attempting to engage but failing to turn the motor.
- No Sound at All: If the battery is confirmed to be good, but there is no sound when you try to start the car, the starter motor may have completely failed.
- Grinding or Whirring Noise: A grinding sound indicates the starter gear is not meshing correctly with the flywheel, or the gear is damaged. A whirring noise without the engine turning over means the starter motor is spinning but not engaging the flywheel.
- Slow or Labored Cranking: If the engine turns over very slowly, it could be a sign of high electrical resistance within a failing starter motor. However, this symptom is also very common with a weak battery.
- Smoke or Burning Smell: Smoke coming from under the car, possibly with a burning smell, can indicate an electrical short or overheating in the starter motor. This is a serious symptom that requires immediate attention.
Choosing the Right Aftermarket Starter
When replacing the starter on a sophisticated vehicle like the S550, part quality is critical. Using a low-quality part can lead to premature failure or even electrical issues with other vehicle systems.
Pro Tip: Both Bosch and Valeo are original equipment (OE) manufacturers for Mercedes-Benz. Choosing a new starter from one of these brands ensures you are getting a part that meets the same specifications as the one installed at the factory.
Brand Tiers for Your S550
- Tier 1 (OEM Quality): Bosch and Valeo are the top choices. They supplied the original parts for these vehicles, so fitment, performance, and longevity will be identical to the factory starter. Bosch also offers remanufactured units that are rebuilt to high standards and offer good value.
- Tier 2 (Quality New Aftermarket): Brands like WAI Global, Remy, and BBB Industries offer 100% new units that provide a good balance of quality and price. These are reliable alternatives to the premium OE brands and are a significant step up from generic, unbranded parts.
A Note on Remanufactured Parts: While premium remanufactured starters from a brand like Bosch are excellent, be cautious with lesser-known remanufacturers. The quality of the internal components and the rebuilding process can vary significantly.
Cost of Replacing an S550 Starter
The total cost will depend on the price of the part you choose and whether you perform the replacement yourself or hire a professional mechanic.
| Item | Estimated Cost |
|---|---|
| New OEM Starter Part | $400 - $800 |
| New Aftermarket Starter Part | $102 - $658 |
| Remanufactured Starter Part | $240 - $375 |
| Shop Labor Cost | $170 - $250 |
| Total Professional Replacement | $570 - $1,050+ |
Frequently Asked Questions
Is it my starter or my battery? 🎬 Watch this owner troubleshoot common S550 starting and battery issues.
This is the most common question for an S550 that won't start. Always test the battery first. A simple voltage test or a load test at an auto parts store can confirm the battery's health. Remember the W221 (2007-2013) has a small starter battery in the engine bay that is a frequent culprit.
🎬 Watch how to easily replace the W221 dedicated starter battery.Can I replace the S550 starter myself?
Yes, this is a feasible DIY job for someone with moderate mechanical experience and the right tools. It requires safely lifting the vehicle and working from underneath. The starter is located on the driver's side of the engine, and access can be tight. 🎬 See this step-by-step starter replacement guide for W221 models. If you are not comfortable working under your vehicle, it is best to leave this job to a professional.
What tools are needed for the replacement?
You will need a good set of metric sockets and wrenches, including 10mm and 13mm sizes for the electrical connections. The two main mounting bolts require an E14 (External Torx) socket. Various extensions and a swivel joint are essential for reaching the bolts. You will also need a jack and jack stands to safely lift the vehicle.
Are there any recalls for the 2007-2016 S550 starter?
No. Searches of the NHTSA database did not find any specific recalls or technical service bulletins (TSBs) related to starter motor failure for the 2007-2016 S550 (W221 and W222 chassis). A recall for a starting current limiter existed for other Mercedes models but did not include the S-Class.
Helpful Videos
Technical Specifications
OEM Part Numbers: 0061515901 0061516001 2789060600 2789060700 2789060800 2789060900
Voltage: 12V, Rotation: Clockwise, Tooth Count: 10
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mercedes-Benz S550: