Engine
Alternator
Alternator Adjuster Nut or Cab Nut (5)
If you’re going to be removing the alternator, I suggest you read this thread/tutorial on how to remove an alternator on a E46 325Ci. This part main function is holding the back cover to the alternator as you can see in the image above.
BMW OEM Part Number: 12427565287 (Supersedes: 12420416297, 12310149379, 61130151017)
Estimated cost: $18
Alternator Cable
These cables commonly corrode, which lead to an array of problems. While researching how to replace your alternator cable, I ran into this thread which talks about some of the benefits of upgrading your alternator power cable and engine ground tables.
Replacing your 20+ year old cables provide the following (www.bimmerforums.com):
- Decrease alternator and starter strain by providing higher current flow to operate.
- Increased stability of electrical system
- Increased stability and current handling of car stereo amplifiers by providing quicker current draw.
- Old corroded, oxidized, greasy, worn ground cables will cause issues such as intermittent starter operation, inaccurate temperature gauge, and dimming head lights.
- Our 2 AWG kits provide faster crank times by allowing the starter to pull more electrical current resulting in reduced engine crank over!
BMW OEM Part Number: 12421439743
Estimated cost: $50
Alternator Pulley
In this video on how to replace an alternator pulley (warning: this is for an E90), but it’s well done and I thought you could use this to troubleshoot your E46 and find out if your alternator is making the same noise.
BMW OEM Part Number: 12317501754
Product Specifications:
| Diameter | 55MM |
Estimated cost: $50
Alternator
Common Alternator Unit Failure Symptoms
- No charge
- Low voltage generated while car is running
- Battery drains even while the car is running
- Dim or flickering exterior or interior lights
- Radio, power windows, sunroof do not function
If you’re thinking about doing it yourself, you should consider watching this video on how to replace an alternator on an E46 2002 330i. On average, I found this job takes about 3 hours.
BMW OEM Part Number: 12317501599, 12317501597, 12317501690, 12311432980, 12311432981, 12311432979, 12311432985, 12311740631
Preferred Aftermarket Brands: Bosch AL0703N, Valeo 439234
Product Specifications:
| Amperage Rating | 120 A |
| Voltage | 14 |
| Plug Clock Rear View Main Mounting Ear at 6 O Clock | 2 |
| Plug Type | 335 |
| Fan Type | Internal |
| Rotation Direction | Clockwise |
| One Wire Capable | No |
| Pulley Included | Yes |
| External Regulator Included | No |
| Pulley Groove Quantity | 6 |
| Case Material | Aluminum |
| Case Color | Aluminum |
| Regulator Type | Internal |
| Pulley Outside Diameter | 50 |
Estimated cost: $300
Electrical Bracket – Cable grommet
BMW OEM Part Number: 61138366627
Estimated cost: $30
Voltage Regulator
If this is your first time doing any kind of electrical work on your E46, you should make sure the battery terminal is disconnected and you’re wearing safety goggles. Since you’ll need to have the alternator out to complete this job, try watching this video on how to remove an E46 alternator.
This part is not that expensive, but if you’re going through all the hassle of taking the car apart, you should probably replace the alternator on your E46 if the vehicle has high mileage or you know the alternator hasn’t been replaced ever.
BMW OEM Part Number: 12317559183
Common Voltage Regular Failure Symptoms
- Low voltage reading when your lights on.
- Car won’t start
- Battery is drained
Estimated cost: $40