Alternator noises

Alternator noises can come from three sources. According to the type of noise from the alternator, the causes that create that noise can be detected. The test is performed while the engine is running. Be careful around drive belts, fans, and other moving components.

A loose belt will squeak. If the engine has more than one drive belt, while the engine is off, rub a bar of soap on the surface of the drive belt pulley. Do this until the noise stops. This way, you will know which belt is the cause of the noise. Check the condition and tension of the belt. Replace the belt if necessary.

Alternator noises

A creaking noise can be caused by faulty bearings in the alternator housing covers. To test the bearing noise, use a longer hose, a longer screwdriver, or a stethoscope. These probes transmit any bearing noise. By placing the probe near the bearings and listening, the noise in the bearing is registered. Bearing replacement will require disassembly of the alternator.

A whining noise can be caused by shorted diodes or stator windings, or a dry rotor bearing. A quick way to test the cause of the whine is to disconnect the wiring from the generator and start the engine. If there is no noise, the cause of a whining sound is magnetic whine due to shorted diodes or stator windings. Check the condition of diodes and stator with measuring instruments. If the noise is still present, the cause is mechanical and probably due to worn bearings.

To perform an alternator noise inspection, follow these steps:

Listening to noise

Start the engine. If necessary, include more powerful consumers in the vehicle. By listening, determine the type of noise (squealing, creaking, or whining).

Locating the source of noise

Based on the type of noise, locate the cause of the noise.

Squealing – check the drive belt.

Creaking – place a narrow hose, a long screwdriver, or a stethoscope near the alternator bearing and listen to its condition.

Whining – disconnect alternator wiring and start the engine. When the noise stops, the problem is with the diodes or the stator windings. If it still whining, it’s the bearings.

Cviljenje – isključiti ožičenje alternatora i startovati motor. Ako nema buke problem su diode ili namotaji statora. Ako i dalje cvili onda su ležajevi.

Eliminating the cause of the noise

Tighten or replace a damaged belt.

Remove and disassemble the alternator cover. Replace the defective bearing.

Repair alternator due to whining (diodes or stator winding).