This article gives detailed instructions on replacing the alternator in a BMW E60/E61 5 series vehicle with the N52 6 cylinder engine. Even though we used a 2006 E61 touring wagon to perform this repair, this article can be applied to any vehicle with the N52 engine including 1,3,5,6,7,X1,X3, and Z4 models with minor modifications to the repair steps.
A BMW E60 alternator replacement may be necessary if you are receiving warnings on your iDrive display and malfunctioning electronics while the engine is running.
As we have discussed in other articles, the BMWs alternator is a surprisingly robust part considering the immense workload it is given every time the car is driven. Not only does it have the job of recharging the battery while the engine is on, but it also powers all of the on board electronics while under constant mechanical and thermal stress in the vehicle’s engine compartment. As many of our BMW E60s approach 15 years in age, the majority of their alternators are still running strong with plenty of service life in them. But if you are receiving any of the telltale signs of failure, then you may be ready for a BMW E60 alternator replacement.
The BMW E60 alternator is located on the front left side of the engine and is driven by the main accessory (serpentine) belt. It effectively turns the engine’s mechanical energy into electricity through its connection to the spinning crankshaft pulley. It uses the energy created from the spinning engine to generate electricity that is used to recharge the vehicle’s battery and power its electronics while driving.
How do I perform a BMW E60 alternator test to verify it needs replacement?
Like all mechanical engine parts in our BMWs, the alternator has a definitive life span and will eventually wear out (no part lasts forever). Unfortunately testing it is not a simple operation. Why? Because of the vehicle’s engine control unit (DME). The DME in your 2006-2010 5 series contains power management software that monitors and adjusts the output from the alternator, so testing its functionality while installed in the vehicle requires special diagnostic equipment.
Most home mechanics (and small repair shops) lack the correct diagnostic equipment to test the alternator in a running BMW E60, so the only other option is to remove it from the vehicle and have it bench tested. If you want to bench test your alternator to determine if it is failing, we suggest contacting your local auto parts store. Most of them have the proper equipment to bench test your alternator to determine if it is operating correctly.
The most common signs of BMW E60 alternator problems are: battery warning light in the instrument cluster, battery warning message on the iDrive display and malfunctioning electronics while the engine is running (interior and exterior lights dimming, electronics randomly turning on and off).
Since several of the above electrical issues can also be attributed to other sources (battery or Intelligent Battery Sensor failure, loose or slipping accessory belt, corroded or broken power cables), it is best practice to diagnose your repair before starting to avoid replacing a perfectly good alternator.
A BMW E60 alternator replacement is a fairly simple repair for the home mechanic with average abilities. The alternator is easily accessible at the top of the engine and there are a minimal amount of parts that need to be cleared out of the work area to remove it.
1. Alternator (required) – The BMW E60 sedan and E61 touring wagon with the N52 engine were originally fitted with either a Bosch or Valeo alternator- their power output was different depending on the type of engine or equipment options. Make sure to match the part number of the alternator you are replacing so it matches your vehicles power system. There are a lot of inexpensive “generic” alternators on the market, but they just don’t last or perform like an OEM quality one. Spending a few extra dollars now on a high quality replacement will save you the frustration of having to repeat this repair in just a few years.
2. Alternator mounting bolts (required) – The alternator mounting bolts on the N52 6 cylinder engine are aluminum “torque-to-yield”…which is a fancy term for they can only be used once. Since an aluminum bolt stretches when torqued, they should always be replaced to ensure your alternator is secured properly to the engine block.
Removing the alternator from the E60 N52 6 cylinder engine is actually a very easy process…even for the home mechanic with average skills. It is anchored to the side of the engine block by four bolts that are easily accessible. ALWAYS disconnect the negative terminal from your vehicle’s battery before starting this repair to avoid damaging any sensitive electronics.
- Locate and identify the alternator on the BMW E60’s N52 engine. It is located at the upper left side of the engine block underneath the oil filter housing.
- In order to access the alternator’s four mounting bolts, the intake muffler must be removed. Start by using a small metal pick to release the plastic retaining clip on the mass air flow (MAF) sensor. With the clip released, use a small flat blade screwdriver to unplug it.
- Use a flat blade screwdriver to loosen the hose clamp anchoring the rubber intake boot to the intake muffler.
- Unsnap the intake muffler lid and remove from the vehicle.
- Use a T30 torx bit to remove the two intake muffler mounting bolts.
- Remove the air filter element.
- Use the T30 torx bit to remove the last intake muffler mounting bolt. Grasp the intake muffler and remove it from the vehicle.
- You now have clear access to the side of the BMW E60 alternator.
- Locate the main accessory belt tensioner pulley on the front of the engine. Use a small flat blade screwdriver to remove its dust cap.
- Using a T50 torx bit and a long handle socket wrench, turn the tensioner pulley clockwise to release the pressure on the main accessory belt.
- With the pressure off of the main accessory belt, reach down and pull the belt off of the tensioner pulley.
- Pull the belt off of the alternator pulley.
- Use an E12 external torx socket to remove the top two alternator mounting bolts. Make sure not to lose the vacuum hose bracket attached to them.
- Remove the lower two mounting bolts.
- Remove the rear electrical connector. We find using a large pair of long nose pliers makes it easier to remove.
- Turn the alternator around so the positive battery cable can accessed. Use a 13mm socket wrench to remove the cable.
- The alternator can now be removed from the vehicle.
Installing the new alternator is simply the above steps in reverse with no special instructions. We have supplied you with a handy step by step installation checklist below with important torque values.
BMW E60 Alternator Replacement Reassembly Checklist
- Attach the positive battery cable to the rear of the new alternator. Torque the battery cable mounting nut to 19 Nm (14 ft-lb).
- Plug the alternator’s electrical connection back in.
- Move the alternator back into position on the side of the engine. Install the four mounting bolts and torque them to: Stage 1 – 10 Nm (7 ft-lb) then Stage 2 – An additional 180 degrees.
- Reinstall the main accessory belt back on the new alternator pulley.
- Retract the tensioner pulley and reinstall the main accessory belt.
- Install the intake muffler back into the vehicle and tighten its three anchor bolts until snug.
- Install the air filter element.
- Install the intake muffler lid back into the rubber intake boot and tighten its hose clamp.
- Plug the mass air flow sensor back in.
- Snap the intake muffler securely on.