Who hasn’t found himself in the situation where his car doesn’t start one morning on the way to work? If it never happened to you , at minimum you’ve already had that apprehension. So when you notice an alternator noise on BMW 3 Series, you can already imagine yourself breaking down, stuck awaiting the tow truck. That’s why our team has decided to produce this post to help you locate the origins of alternator sounds. In this article, you will first see the role and functions of the alternator in your BMW 3 Series and then what the causes and solutions to alternator noise on BMW 3 Series may be.alternator-noise-bmw-3-series

Role and alternator operation BMW 3 Series

Alternator role

Your alternator is an fundamental component of your BMW 3 Series. Indeed, its goal is to provide power to your entire electrical system: headlights, interior lighting, signalling, computer… It will have the mission of recharging the battery once the car is in motion, to provide power to the car in motion and to let you to always have a sufficient energy reserve to be able to restart the next time.

Alternator functioning

The alternator operates on an electrical principle that has been used for decades, the concept of copper coil wound around a magnet . This coil while rotating makes electricity. It is the engine motor itself that will provide the energy requested by the alternator to create the energy, via the accessory belt or alternator belt. When your BMW 3 Series engine stops, the battery takes over to provide the car with energy.

What are the several alternator noises or sounds on my BMW 3 Series and what are the causes?

I notice a knocking noise caused by the alternator of my BMW 3 Series

One of the characteristic noises of a tired alternator on BMW 3 Series is a knocking noise. This alternator sound on BMW 3 Series will most of the time show up when your engine is idling, it can be linked to voltage drops that could affect the normal operation of electrical parts such as headlights for example. In general, it is a of both bearings of the alternator that is malfunctioning, to verify it, use a multimeter on the terminals of your car with the engine running and you must get a value between 12 and 14.7 volts, which means that your alternator is recharging your battery well. If the value is lower, the alternator of your BMW 3 Series is tired and you should consider swapping the bearing if it is the only cause otherwise the whole part.

I notice a grinding noise coming from the alternator of my BMW 3 Series

If you are in the situation where the alternator of your BMW 3 Series causes grinding sounds, in this circumstance you will have to check it more seriously. This sign can testify as for the knocking sound of a tired bearing, but usually, we often realize by looking more meticulously that it is the accessory belt that is loosened or worn and is therefore the cause of it. In this circumstance, we recommend that you consult this document to find all the necessary details to solve an accessory belt noise on BMW 3 Series.

I notice a loud noise from the alternator of my BMW 3 Series

Listening a loud noise from the alternator of your BMW 3 Series is quite normal, in fact, it emits an audible sound when producing the electrical pulses it generates. It is up to you to verify that the battery indicator light on your dashboard does not appear, and that you do not have a voltage drop when your engine is running (headlight or dashboard light that jumps for example. If this noise is too loud, we recommend that you have a look this document to find other ways to solve problem of noises from front end on BMW 3 Series.