A 12-volt battery powers the electrical system in your vehicle. The initial job of the battery is to power the starter motor, thus cranking the engine fast enough to start. The battery also supplies voltage to the ignition system, the fuel system, lights, HVAC system, windows, door locks and multitudes of other electrical consumers throughout the car. In order to maintain the battery in a state of charge, a belt-driven electrical generator, generally referred to as an alternator, is bolted to the engine block. The belt driving the alternator is powered by the engine pulley (vibration damper). As soon as the engine starts, electrical power is generated by the alternator and supplied to the battery to recharge it.

Generation of electricity creates a significant amount of heat in the inner windings of the alternator. This heat needs to be vented and dispersed in order to prevent damage to the alternator. Air-cooling of the alternator is used in nearly all car models and most BMW models.

A faulty or failing alternator can cause many problems, from a simple discharging of the battery to an engine drivability problem. There are a few signs and tests you can perform to determine if the alternator is the root cause of your problem. If you get lucky, your battery light (charging system indicator) will illuminate to warn you of a possible failure. When the battery light (charging system indicator) is ON, this means a voltage difference has been detected between battery positive (+) constant (terminal 30) and ignition ON circuit (terminal 15), indicating a fault in the charging system.

It is common for an alternator to fail slowly. When this begins to happen, your symptoms will be present when the electrical system has the highest load, for example at night. Driving at night, you may notice the instrument panel lights dim, or the radio or headlights flicker. This is a good indication that the alternator cannot handle the excess load. Another sign of a charging system problem is the headlights dim or radio sound goes down when lowering your window. When the alternator can no longer charge the battery, you may park your vehicle and not be able to start it. Of course this could be a faulty battery too.

Always check the voltage of your charging system under load; voltage should be within 13.2-14.5 volts dc. To load, have the engine running at idle, turn on the headlights and HVAC blower motor. Never disconnect a battery cable while the engine is running to test the alternator; you may cause damage to the alternator or other electrical components from the surge in amperage. Before performing any tests of your alternator, charge and test your battery. If the battery is faulty, your alternator tests will not be accurate.

In this article, I'll go over the steps involved with replacing the alternator on the BMW Z3 4 and 6-cylinder engines. Be sure to work with a cool engine and disconnect the battery before beginning. Z3 models can come with a few alternator amperage ratings. Be sure your replacement alternator has the same rating as the faulty unit. You can usually find the amperage rating on the alternator housing.

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out the body or interior items.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Working in the trunk, disconnect the battery negative cable and cover the battery terminal so the cable does not accidentally come in contact with the disconnected cable. See our tech article on battery replacing for notes on disconnecting and reconnecting the battery.

Read the Full Article: https://www.pelicanparts.com/BMW/techarticles/BMW-Z3/17-ENGINE-Alternator_Replacement/17-ENGINE-Alternator_Replacement.htm

Project Time: 3 hours
Tab: $300
Tools: Set of sockets, 17mm open-end wrench, flathead and Phillips screwdrivers, needle nose pliers
Parts Required: Alternator, drive belt, idler pulley
Performance Gain: Car will charge properly
Complementary Modification: Change serpentine belt, idler pulley.

Hochgeladen am 11.04.2022   Problem melden   Dieses Video bei YouTube   Pelican Parts bei Youtube