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Alternator Replacement

BMW Z4 Alternator Replacement Cost

The average cost for a BMW Z4 Alternator Replacement is between $500 and $778. Labor costs are estimated between $149 and $189 while parts are priced between $351 and $589. Estimate does not include taxes and fees.
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How Much Does an Alternator Replacement Cost?

Alternator Replacement Service and Cost

Alternator Replacement
What is an alternator?

All of the electrical components on a vehicle need electrical power to operate, and the battery has a finite amount of storage. This creates the need for a built-in battery charger called the alternator, which works in conjunction with the battery and starter to form the starting and charging system.

How does the alternator work?

The alternator is mounted on the engine, and creates power much like a wind-energy turbine, except it is turned by the serpentine belt, or accessory drive belt instead of wind. As it spins, it creates electricity, and the built-in voltage regulator and rectifier are responsible for ensuring the current is correct for the vehicle.

What are the symptoms related to a bad alternator?

Alternator failure while driving will cause the battery light to illuminate on the dashboard. Soon after, all electrical components will being to lose power, the vehicle will stall, and jump-starting will not be effective. The alternator can also fail due to the bearing that holds the internal rotating assembly, causing a grinding noise that changes with engine speed.

Can I drive with an alternator problem?

A vehicle with a weak alternator may be able to drive to a repair facility for diagnosis, but a vehicle with a failed alternator will not run after an external charger is removed from the battery.

How often do alternators need to be replaced?

Alternator failure is seemingly common, but in most cases an alternator can last 100,000 - 150,000 miles without incident. Harsh driving conditions, and aftermarket electrically powered accessories can decrease the useful life of the alternator.

Alternator Replacement Repair Information

How are alternator issues diagnosed?

Since the alternator is part of a group of components known as the starting and charging system, when there is a failure, the entire system must be tested to prevent mis-diagnosis, and unnecessary component replacement. Repair facilities use professional starting and charging system test equipment that automatically or manually tests every component in the starting and charging system simultaneously, and definitively. Prior to this test being conducted, the entire system must be physically inspected for damage, or lack of continuity.

How is an alternator replaced?

When replacing the alternator, the technician must remove the battery cables to prevent electric shock. Afterwards, the accessory drive belts or serpentine belts must be removed from the alternator, along with electrical connectors, and several bolts. Once the bolts are removed, the alternator is free from the alternator brackets, and can be removed. Replacement is in reverse order, and proper torque must be applied to prevent damage. The vehicle will then be retested in the same manner to ensure the repair is complete.

RepairPal Recommendations for alternator issues

Since the alternator requires the removal of the serpentine belt, replacing the serpentine belt is recommended if the belt is worn, or the service interval has been reached. If the battery cables were identified as having physical damage or extensive corrosion, they should be replaced as well.

What to look out for when dealing with alternator issues

On most modern vehicle's, the amount of room to work can be extremely limited, and that can play a significant role in repair cost. In some cases suspension components, drive axles, cooling fans, and bumpers must be removed to access the alternator. The manufacturer supplies an alternator with the vehicle that produces appropriate amperage for the original components. If additional electrical components are installed, the new alternator should be of a sufficient grade to handle additional power demands.

Can I replace the alternator myself?

As mentioned before, the alternator can be placed in a location that is inaccessible without extensive deconstruction. In these cases, the replacement should be left to a professional technician to prevent damage, or improper installation of sensitive components. If the location of the alternator is accessible, a good understanding of starting and charging system diagnostics and repair can make this job a cost-saving DIY.

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