I think the time has come for my Mini to receive a new alternator at 165,000 miles and was wondering which alternator option would be the best to go with. I'm debating just replacing the battery first, but I think the real issue is with voltage output.

I've had problems recently perhaps spurred on by the cold weather with my power steering + all electrical systems cutting out while parallel parking (low speed while turning the wheel kind of hard) before they jolt back on in less than 10 seconds. However, this is dangerous as it's cut out mid turn almost resulting in a bumper tap with the car in front of me because the steering went dead unexpectedly. It started to shut down on me while driving on the street doing 25-30mph, right before merging onto the highway at a stop sign, and just doing necessary day to day maneuvers.

There are no trouble codes apart from P0500 which only came on after all the electrical systems shut down and then restarted. I'm getting jumpy voltage 13.1 to 13.9 while driving with minimal accessories on (blower fan/heat off, radio off), sometimes the voltage drops down incredibly low to 12.1 to 12.6 when the stage 1 fan comes on then ticks back up incredibly slowly, this is definitely not normal right? Sometimes the voltage output will read 14.0 volts, but then it just dips down or I'll encounter random electrical shutdowns, it's like chasing a ghost.

Would the best bet be going with the original Denso alternator for $400 or should I spend half that on a new battery?

 

I'm not sure if this is your issue. Some of the symptoms mirrored mine to some degree.
Here is what I ultimately discovered:R53-Confusing voltage drain .
Although you haven't specified the year or model of your Mini; It may be prudent to check the -"Ground bus X175" nut /connection first before spending and swapping unnecessary parts.

 

It’s a 2005 R53. Where is the ground bus X175 located?

EDIT: Nevermind, pictures weren’t loading. I’ll take a look at it tomorrow morning, I hope it’s as simple as that.

My problem sounds somewhat similar, but it according to the OBC the voltage doesn’t dip to zero when the cooling fan engages. It usually just goes down to 12.1 to 12.6, then after shutting off the voltage returns to ~13.

Unfortunately it isn’t enough power to support the accessories and more importantly the power steering pump. Makes me wonder if the PS pump is going bad.

 

I have a 2005. Mine pukes a battery up every 5 years. Get the one you have load tested. My alternator with 155k is original. When the battery gets weak, the car goes nuts.

 

The Ground Bus X175 is located on the left (driver side) directly underneath the hood latch cable. My Mini is a pre-facelift '04 R53 (late 2003 build). I have 2 Ground Bus' in the same locations on each side = right passenger side and one on the left driver side directly under the hood latch cables. I understand that In July 2004 the R53 underwent a "facelift". There were some changes made at that time; So your '05 may only have one...or none at all.
BMW may have changed the Bus alltogether in later models. However, If you do happen to locate one/them; Check the tightness of the nut or in any case remove the Bus and make sure it's contact point to where it's mounted is shiny and clean. I hope this may be the answer to our similar problem.

 

Pwi

 

@DFTR "PWI stands for Person Without Intelligence. IE: Somebody who doesn't think about what they are doing/writing."
Not implying - But Is that in response to my post/reply?

To the point of the OP's post - You maybe right . I did not answer the question regarding preference in Alternators...or other major components causing fault.

 

In my case I deleted the stupid thing I wrote as I was: "Posting While Intoxicated ".
sorry.

 

Thanks for that. I am not current in deciphering/understanding acronyms. I was a bit confused.

 

So I tested the battery (Walmart Everstart MAXX-5) at my local autozone, it was at 54% charge at 12.24 volts but the guy said the battery was still good. Date code on the battery is March 2019.

I'll try charging the battery up a bit.

 

If you change the alternator, get a Denso - as far as I can tell, a lot of the rebuilds vary in quality.

 

Yes, try this, see if it will expand its charge or not, this will give you a good indicator of battery -vs- alternator since you can get an exact voltage reading to check against the other.

Quite frankly, I personally just use AP store alternators, no reason to go to the dealer.
I believe Denso is the factory replacement (it's been a while, don't quote me) but honestly I've had best luck with the O'Reiley's Ultima units, plus it's a quick (for me) replacement if there's an issue, even though I haven't had one.
​​​​​​
IMO stay away from Rock-Auto offerings, alternator are the one thing I've had problems with from them (had 2 burn up on me) plus the "getting the car back in the road in a timely manor" issue.

 

So, looking at the multimeter connected directly to the battery (all accessories off except the DRLs / interior dash lighting) it reads 14.1-14.2 volts - which is where it should be right?
The OBC doesn't get up to that voltage readout only between 13.8-14.

 

Yeah, that is normal for a functioning alternator. I see ~14.0 V on my OBDII readout. I believe the Bentley quotes 13.5-14.5 as the acceptable range.

 

Good to know, I guess the battery may have just gotten discharged too much while running accessories on short trips + power steering pump load + the cold, or there might be something else that's funky going on with the electrical system.

 

I got a denso reman off of amazon a few years ago when my alternator died. It's 3 or 4 years old now and still going strong. just my 2 cents.

 

The power steering pump and all electrical power keep shutting down, happened last night while pulling out of a tight spot.

This seems like symptoms of a failing power steering pump from what I've read, where the pump is over drawing power as the pump starts to go out. The power steering functions well apart from those intermittent electrical shutdowns, I don't think I would qualify for the recall anyway considering the mileage and also the mfg date.

 

Call a dealer and have them check on the recall for you. In August 2021, I bought an R53 with 104K miles and manufacture date of 09/2002. I had the recall work done in October.