Mercedes-Benz 400SEL Alternator Repair at your home or office.

Our certified mechanics come to you・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing
Logo-yelp
CUSTOMERS LOVE US ON YELP
4.5 out of 5 (550 reviews)
Icon-warranty_badge-02
SERVICES BACKED BY OUR
12-Month, 12,000-Mile Warranty
How does YourMechanic work?    
Icon-quote-hiw
Get a quote

Choose from 600+ repair, maintenance, and diagnostic services, backed by our 12-month, 12,000-mile warranty.

Icon-calendar-hiw
Book an appointment

Tell us when to meet you at your home or office. We’ll send one of our vetted, top-rated mechanics.

Icon-fixed-hiw
Get your car fixed

Continue with your day while our mechanic fixes your car onsite. You pay only after the job is done.

Alternator Repair Estimate for Mercedes-Benz 400SEL

Mercedes-Benz 400SEL Alternator Repair costs $321 on average. Following is a breakdown of the labor and parts estimates.

YourMechanic Price
$317 to $335
Labor: $126 -$144
Parts: $191
Average Dealer price
$555
Average Shop price
$394
Get an instant quote for your car
Our mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing
Get a quote
CarServiceEstimateShop/Dealer Price
1993 Mercedes-Benz 400SELV8-4.2LService typeAlternator RepairEstimate$508.16Shop/Dealer Price$648.37 - $968.49
Show example Mercedes-Benz 400SEL Alternator Repair prices

Service

What is an alternator and how does it work?

The alternator, which is bolted to the engine, keeps your car’s battery charged and produces the electrical power necessary to run the vehicle’s electrical systems. When starting your car, stored energy in the battery powers the starter motor. Once the engine is running, the alternator produces the electrical energy that your car needs by spinning a magnet on a rotor through a stationary coil of wire. To ensure that the alternator provides the right voltage output for your car’s electrical system, there is a voltage regulator built into the alternator. The voltage regulation is built into the car’s Powertrain Control Module (PCM) on newer vehicles.

Alternator

When to replace the alternator?

The following electrical or mechanical faults are signs that the alternator may need to be replaced:

  • Battery or charging system warning light. If a warning light has illuminated, the charging system and the vehicle battery should be tested to pinpoint the fault.
  • Difficulty starting your car or it doesn’t start. A faulty alternator will lead to the battery being discharged. Once the battery has discharged enough, you will have difficulty starting your car or it won’t start at all.
  • Dimming lights. Should the alternator have an internal electrical fault, such as a burned-out diode or open stator windings, the alternator will have less capacity to provide electrical power.
  • Grinding or whining noise. High heat created by the engine dries out the grease in the alternator bearings, wear occurs, and then the alternator can emit a grinding or whining noise as it spins. Certain electrical failures within an alternator can also cause a whining noise.
  • Premature Battery Failure. If the voltage regulator within the alternator has failed, and thus charging system output is too high, that can cause the battery to fail due to overcharging. Although this fault is not as common as a weak alternator, the possibility should always be considered if your car battery fails prematurely.
  • On an annual basis, or every 12,000 miles. The voltage output of the alternator should be carefully measured and compared to the OEM factory specification. Voltage output should also be checked whenever the vehicle battery is replaced.

How do mechanics replace an alternator?

  • Disconnect the battery prior to replacing the alternator, as with all electrical repairs.
  • Unhook the drive belt connected to the alternator.
  • The electrical connections to the alternator are removed and the alternator is unbolted from its cradle on the engine.
  • The new alternator is installed while observing all factory bolt torque specifications. Alternators have to be mounted to the engine very securely because they rotate at high speed. Electrical connections are cleaned and re-attached, including the connections to the battery.
  • While the drive belt is off, best practice is to inspect the drive belt as well as inspect all pulleys driven by the belt.
  • Once all components are securely in place, the vehicle engine is run and the output of the new alternator is measured and verified against the OEM factory specification.

Is it safe to drive with an alternator problem?

One should exercise caution. Should the alternator fail while you are driving, the battery alone will power the car’s electrical system for a short while. Cars require a substantial amount of electrical power though and the battery will likely discharge relatively quickly. The car may stall and it would be impossible to re-start if the battery discharged completely. When the battery or charging system warning light illuminates, the situation should be investigated and resolved as soon as possible.

When replacing the alternator keep in mind:

  • An alternator should always be tested to be sure it is actually faulty versus a circumstance where faulty electrical connections, or an open fuse, might be the problem.
  • An alternator that has noisy or worn out bearings should be replaced regardless of electrical test results.
  • A properly functioning battery is very important in modern cars and consequently the battery should be load tested when the alternator is replaced.
  • Alternators are designed to power all vehicle electronics and maintain a fully charged battery but if the battery has failed and won’t hold a charge, attempting to continually re-charge such a battery by driving can overload the alternator. Replace the battery and avoid repeatedly jump-starting your car.
  • Electrical connections, including grounds, are very important in the charging system. When replacing the alternator, all disconnected terminals should be inspected and cleaned and then checked to be sure all connections are properly tightened.

Fast and easy service at your home or office.

GET A QUOTE FOR YOUR CAR
Backed by 12-month, 12,000-mile guarantee

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.

1-800-701-6230 · hi@yourmechanic.com