You want full reliability for your BMW E46 323i 323ci 328i 328ci 325i 325ci 325i 330i 330ci?
I've compiled a list of parts that based on my experience are known to leave you stranded. If your car is over 10 years old or has more than 100,000 miles on it, then there's a fairly good chance these will leave you stranded. Good news is that these are cheap and easy to replace. Replace them and easily get another 10 years and 100,000+ miles out of your car. Trouble free operation. Nothing worse than being stranded especially with your kids or your wife in the car.
Electrical and Ignition
This is by far the most important part of the list!
Battery - $90-$150
BMW part# 61218381749
Every 5 years or so, your battery's ability to hold charge.
If your battery is five years old or older, or you don't know - replace it. This will cost between $90 and $200. Try Autozone, Walmart, Costco, etc. Make sure the battery you purchase comes w/ a vent tube kit. This item is best bought in person. Sorry no online link to it.
Voltage regulator - $50
purchase here - square plug voltage regulator Bosch
(your car may require a oval/round plug regulator.) Usually it's 04+ cars that require this. Check your connector to be sure if it's rectangle or rounded.
How does the voltage regulator go bad?
You may suddenly get a battery light while driving down the road one day. It may flicker or stay on. Either way, your voltage regulator is toast. The brushes that make contact with the alternator have worn down. If you have a Valeo alternator, it makes sense to just replace the entire alternator as replacing just the voltage regulator is around $150. You will have to look with your eyes to see which voltage regulator you need.
Final Stage Resistor - Only $40!
VERY IMPORTANT! Can cause your car to drain its battery by itself while parked or worse yet catch fire. VERY problem prone. Another symptom is your AC won't blow air at all. If the blower speed is intermittent or non-existent, very high chance that this has failed. Purchase the NEW revised updated design by BMW here: Final Stage Resistor
E46 starter motor
Key - $160 at your local dealer
Bring your registration and driver's license to the local BMW dealer. Order a new key. They've been known to fail (though rarely) and all the new parts in the world won't mean anything with a busted key. Plus a new one looks so nice. Expect to pay around $160-200.
Ignition Coil Spark Plug Boots f
Bosch coils part number 12131740477 or for Bremi coils: part number 12139067831
These can sometimes go bad on BMWs. Intermittent electrical errors when you turn the key. Wonky dashlights when you turn the key or while driving.
Crankshaft Position Sensor
Camshaft Position Sensor - Intake
Camshaft Position Sensor - Exhaust
Fuel Pump - MAJOR FAILURE ITEM!!!
*Buy a universal clamp! A member recommended size 1/4-5/8"*
DO NOT FORGET THE SEALING RING or you will SMELL FUEL in your car and have fuel leaks. Fuel Pump Sealing Ring
Fuel pump relay
Crankcase vent valve kit: Genuine BMW CCV Kit
Or if you need pieces separately:
Vent pipe (attaches to valve cover) 11611432559
Vent pipe #2 (attaches to top of CCV valve) 11617504535
Vent pipe #3 (attaches to bottom of ccv and dipstick tube) 11157532649
Vacuum hose 11727545323 (attaches to side of ccv)
Vent pipe #4 11617504536
Manual cars/Clutch Hydraulics
Clutch line, part number 21526774267
Clutch master cylinder, 21526773670 - Purchase here
Clutch slave cylinder, part number Purchase here -21526785966
Grand total manual cars: $1,096-$1,306
Grand total automatic cars: $956-$1,156
DME compartment. Remove cover, clean/vacuum/condition seal w/ gummipflege. Inspect for any leaves, dirt, or debris or anything weird with the wires. Never know what previous owner junked up the wires doing teenager angel eye wiring! Make sure any splices or cuts are properly joined/repaired, well protected, and insulated.
Inspect all wiring harnesses and plugs for damage or exposure. Re-wrap any exposed wiring harnesses with new loom if the loom has broken off or disintegrated. Remove all sensors and clean with electrical contact cleaner then apply dielectric grease to the pins/contacts.
Links, part #s, prices subject to change. Check your particular car and requirement for your particular needs. Always hire a professional to do work. This goes for every page and link on this site. If you decide to perform work yourself, always work safely using appropriate safety equipment and procedures.