"While you're there..." 2 Great things to check.

[js22]

Whenever you start digging into a car to do 1 thing, there are always other things that you really should do "While You're There." Usually each item added to the list adds to your cost, and if you're not careful there's a risk that you'll end up manufacturing a brand new vehicle at only 17x the original price...

I'm prepping a replacement engine for my 330xi so I'm in the middle of all sorts of "while you're there" stuff.

One thing that's been nagging at me for a while was the starter. Replacing a starter on a complete E46 is not fun, AFAICT. But do I want to shell out for a new one just because? No, I do not. Well, it took a surprisingly long time before the (totally obvious) solution occurred to me : JUST LOOK AT IT!!!

Here's a pic of the Bosch starter with three easy bolts/nuts loosened.




I pulled the guts out of the can, and here's a view of one of the brushes from what I'll call the "back" side.



I'm pointing the screwdrivwer at the place where the braided copper conductor connects to the brush. That brush (it's surface is red) could not be pushed any more away from the commutator (i.e. to the right.) So it's pretty close to brand new, says me. Here's the other ("front") side of the brush.



The one that the screwdriver is pointing at is solid carbon to (almost) the very end of the slot. The one above it is seen end-on; the back side of the carbon is right up near the top of the tube: the spring doesn't have much more room to compress.

So the takeaway here is that I can put this starter in my car and have zero concern that it's gonna die any day now. And if I did find that the brushes were worn, I could have either bought a replacement cartridge/thingie for about $25 or another starter. And I wouldn't feel bad, because it had to be done.

Maybe not as big a time-saver, but right up the same alley are the alternator brushes. I used to just drive a car until the "alternator died" and then replace it. Then I learned that you can drive a car until the "alternator dies" and replace just the part of it that actually fails: the brushes. Usually there's a cheap little module you can buy and swap out in no time. But in this recent flurry of "shoulda realized that 35 years ago" somethng truly amazing dawned on me: You can actually look at your alternator brushes before your alternator dies! I know, right?

The thing I learned though was that the little module for the Valeo alternator (some E46's have Valeo, some have Bosch) is in the $90-180 range! To me, that's just Krazy, with a K.

Anyway, I opened up my Valeo alternator, removed the module, and here's what I found:



Those brushes are about 2 trips to the grocery store away from wearing out. Here's another view after (ever so gently) removing the protective dust cap.


There's probably a spec for how short the brushes can get before you have to replace them, but I'd gues its about "yae long".

So what's a CSOB supposed to do? Well, it turns out if you can do basic soldering, there is a cheaper way. The actual brushes in all Valeo alternators ever made anywhere are all the same. (But check that you get 4.5 x 6.5 mm, just to be sure...) And a pair of them on Ebay is $7 with free shipping. There are videos online showing how to replace them, but it's a basic unsolder/solder operation. Here's the back side showing the soldered copper leads poking through:


That black blob is some RTV I pulled off w/ my fingers. I just ordered the brushes, so no "after" pic.


I know that theoretically, there are ways that a starter or alternator can fail besides the brushes, but I'd wager they are pretty rare. Bearings and diodes and copper wire and metal housings can easily last several times the life of a car. Brushes, however, are designed to wear out. If you don't know how old/worn your brushes are, you are driving on borrowed time. And "while you're there", it is super easy to check.

[Manolito]

You did not mention the miles on your original 330 engine. I loved my two e36s more than I love my two e46s, but I must concede that a LOT more little things failed on the e36s in the first 200k miles than have failed on the e46s.
My daily driver touring has 252k miles on it and I just ordered a new voltage regulator w/brushes because my experience with Bosch alternators on Volvos and BMWs is that about 250k miles is when they give up. The voltage regulator for a Bosch is only $30.
On your car, I would replace the plastic water pipe on the driver side of the engine and the crankcase ventilator while it is out. If it is a manual transmission, I would replace the clutch, and if high miles, the flywheel.