3.0L M54 engine whirring noise

[oldskewel]

All bets are off with the hammer, now.

It's a tight fit going back in. I generally remove whatever is needed so I can align things properly, and use some antiseize on all the contact surfaces just so things don't bind.

With those trips ahead of you, and your new diagnosis info, I'd say to swap in the new one ASAP. I definitely would not risk an alternator suddenly dying on trips like that. This is no longer a normal wear and tear issue.

BTW, now apparently unrelated, but here is an example of extreme slip ring wear on the Denso alternator from my old Lexus that had a notorious issue with PSF leaking onto the alternator. The copper has worn all the way through, and that patch of brown is the underlying plastic. As always happens with alternator slip rings, one of them wears a lot more than the other. That phenomenon is due to the electric field's effect on the freed copper ions. I have not done it, but @AndrewWynn did an electrical polarity swap on his alternator to shift the balance to the other one.



Second pic is the new, replacement slip rings before I installed them (not easy at all).

[rmr2122]

I'll try to get the swap done before I leave next week. Could two light taps with a mallet really destroy an alternator though? I didn't even mar the casing the slightest bit!

[Bdc101]

I used an even mix of hammer and pry bar to get my alternator back in, to answer your question, and it's been working fine ever since.

[andrewwynn]

The insert nut is press fit. Put the bolt partly installed and hit the bolt to give yourself a mm or so to work with; the alternator will not fight you at all getting on the bracket.

The last time I installed one I took out and installed from the front by removing the belt tensioner that was in the way. Pros and cons either way. I usually remove the disa valve for working space but think I skipped that the last time by going out the front vs up the side.

[ahlem]

BTDT. Here's what I did to get the alternator out of my 2001.

https://xoutpost.com/bmw-sav-forums/...oval-tool.html

[oldskewel]

Originally Posted by rmr2122

I'll try to get the swap done before I leave next week. Could two light taps with a mallet really destroy an alternator though? I didn't even mar the casing the slightest bit!

I wouldn't normally think it would be a problem. But given that you've isolated the alternator as the source of that noise, and that you R+R'ed the alternator during the time when this problem appeared, that all leads me to think some damage was done. It's a spinning thing with bendable internal parts (fan blades, for example) and close tolerances in there. Maybe you knocked loose a chunk of solidified gunk or something? Hit the pulley? As you get in there, you should be able to confirm what is wrong. Bench test if you need.

And "destroy an alternator" - not like you blew it up, you just need to have dinged it in the wrong way. May be fixable (maybe even using the hammer ), but I would not rely on it during a road trip at this point.