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BMW E39 Alternator Removal
 
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Pelican Technical Article:

BMW E39 Alternator Removal

Kerry Jonsson

Time:

3 hours3 hrs

Tab:

$300

Talent:

****

Tools:

13mm, 16mm, socket with ratchet, small thin pick, flat head screwdriver

Applicable Models:

BMW 525i Sedan/Wagon (2001-03)
BMW 528i Sedan/Wagon (1997-00)
BMW 530i Sedan (2001-03)
BMW 540i Sedan/Wagon (1997-03)

Parts Required:

alternator, tensioner, accessory drive belt

Hot Tip:

Remove the air filter housing to get more room to work

Performance Gain:

Replace alternator that is not charging or has bearing noise

Complementary Modification:

Replace the tensioner and accessory drive belt at the same time

Although automobiles are powered by the engine, it all starts with the electrical energy stored in a battery being applied to a starter motor to start the engine. Running the starter and the car draws electrical current. To supply this electrical power an alternator changes the engines rotating power into electrical energy therefore replenishing electrical energy to the battery. If an alternator fails the engine will only run as long as the battery can supply power. When the battery runs out of electrical power the engine will stop running. In this tech article we will go over all the steps to change the alternator on your E39 (except the water cooled models).

In order to remove the alternator you will need to remove the cooling fan, shroud, and accessory drive belt. See our tech articles on removing these components and follow the steps from there.

Alternator Removal Six Cylinder:
Disconnect the battery negative terminal to open the circuit and remove all electrical power from the car.
Figure 1

Disconnect the battery negative terminal to open the circuit and remove all electrical power from the car.

Working at the front of the engine remove the upper idler pulley mounting fastener with a 16mm wrench or socket w/ratchet.
Figure 2

Working at the front of the engine remove the upper idler pulley mounting fastener with a 16mm wrench or socket w/ratchet.

Remove the lower 16mm alternator mounting bolt (green arrow) below the alternator.
Figure 3

Remove the lower 16mm alternator mounting bolt (green arrow) below the alternator.

Pull up on the alternator to remove it from the lower mount.
Figure 4

Pull up on the alternator to remove it from the lower mount. You can use a pry bar to lever up on the alternator to remove it because it will be a tight fit.

Tilt the alternator downward.
Figure 5

Tilt the alternator downward. At the back of the alternator press on the retaining clip (green arrow) for the small connector and unplug it by pulling it in the direction of the blue arrow.

Use a 13mm socket to remove the alternator positive cable mounting fastener (green arrow).
Figure 6

Use a 13mm socket to remove the alternator positive cable mounting fastener (green arrow). You can now pull the alternator out of the car. To install the alternator, reverse the steps for removing. Remember to route all wiring as it was before and check the charging system and drive belt alignment when complete. 

Alternator Removal Eight Cylinder Engine:

In order to remove the alternator on the eight cylinder engine you will need to remove the cooling fan, shroud, accessory drive belt and tensioner. Follow the instruction in our tech article on how to remove these components and follow these steps from there.
Disconnect the battery negative terminal to open the circuit and remove all electrical power from the car.
Figure 7

Disconnect the battery negative terminal to open the circuit and remove all electrical power from the car.

Remove the belt tensioner.
Figure 8

Remove the belt tensioner. Next remove the 13mm lower mounting bolt of the alternator. This is the last mounting bolt for the alternator. The first two were removed when you removed the belt tensioner.

You will not be able to pull the alternator forward to removing the wiring from the back.
Figure 9

You will not be able to pull the alternator forward to removing the wiring from the back. Look at the back of the alternator between the engine and the body of the car and remove the 13mm nut (green arrow) that mounts the positive battery lead to the alternator.

Now you can move the alternator forward.
Figure 10

Now you can move the alternator forward. Unplug the small connector by squeezing the retaining clip and pulling the connector in the direction of the blue arrow. You can now remove the alternator from the car. To install the alternator, reverse the steps for removing. Remember to route all wiring as it was before and check the charging system and drive belt alignment when complete.

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Comments and Suggestions:
Ian Comments: I have now replaced the alternator four times in less than two years!!! Each time, it reads that the voltage regulator has failed. How is this happening? The voltage regulator is integrated into the alternator isn't it? Why is it continually failing? Is there something else on the car that could be killing the voltage regulator? How do I find it and solve it?
March 30, 2017
  Followup from the Pelican Staff: I'd verify that the battery is in good shape first. Also I have had issues with the Bosch reman alternators, I finally just coughed up the bucks for a Genuine BMW one... BUT in your case I would recommend performing a voltage measurement at the alternator and comparing that to the measurement at the battery while the electrical system is loaded up to the max...A/C on MAX, defrosters on, seat heaters on headlights on, foglights on. You should have no more that .5 v difference. If you do then you have too much resistance on the B+ circuit and this needs to be fixed. - Casey at Pelican Parts  
Enrique Comments: Thanks for these great directions. Do you all have the torque specs for the bolts by chance? That would be the only thing lacking here. Scouring the internet seeking that info.
December 31, 2016
  Followup from the Pelican Staff: I don’t have torque information.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 

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Page last updated: Sat 4/29/2017 02:05:09 AM