Alternator 2006 S60 R; also Chicago area shop recommendations? [ How long can I run a P2 on just a battery]

[cn90]

Different components fail in different ways.

The predictable:
- The Bosch front bearing is usually from Koyo, very good bearing. This should last 180K-200K, at that time, it makes noise and is free-wheeling (with belt removed for testing).
This usually makes noise and can be diagnosed using stethoscope etc.
- The copper rings usually wear down to nothing at 200K.
- Ditto with the brushes (usually built into the VR).

The unpredictable:
- The VR itself is a complete crapshoot.
It can fail at 40K-50K.
But it can last some 300K-400K (assuming the alternator is rebuilt with new bearings, copper rings etc).

So for cars with 180K-200K, I just drive around town.
For long trips, just rent a car, one saves money by renting a car bc one puts wear/tear on the rental car.

[cn90]

Another trick if one has to go home with no time to change alternator...when dealing with this issue to avoid towing halfway through.

Buy a new battery ($120 at Costco for Interstate)...charge it well, then make the trip, approx 45 min later swap battery.
At next stop, charge both batteries etc.

Anyway, a few cycles of discharge will significantly shorten the life of the battery...

PS: another option is to carry a spare used alternator in the trunk for long trip. Go to junk yard or eBay and get an alternator ahead of time for let's say $35-$50. Bench test it first (AutoZone etc). Then bring it along for long trip. The money spent here is worth it considering the inconvenience of towing etc. Also, if and whenever you sell the car, you can always resell this used alternator on eBay etc. so you are not losing much money here.

[erikv11]

Different components fail in different ways.

The predictable:
- The Bosch front bearing is usually from Koyo, very good bearing. This should last 180K-200K, at that time, it makes noise and is free-wheeling (with belt removed for testing).
This usually makes noise and can be diagnosed using stethoscope etc.
- The copper rings usually wear down to nothing at 200K.
- Ditto with the brushes (usually built into the VR).

The unpredictable:
- The VR itself is a complete crapshoot.
It can fail at 40K-50K.
But it can last some 300K-400K (assuming the alternator is rebuilt with new bearings, copper rings etc).

So for cars with 180K-200K, I just drive around town.
For long trips, just rent a car, one saves money by renting a car bc one puts wear/tear on the rental car.

My impression is the issue with this alternator is none of that, mechanically it is fine, but it likely has a failed diode.

I drive my high mileage cars all over the country. I don't carry a bunch of replacement parts. Instead I buy AAA membership just for the towing service. The tow gets you out of trouble for a broad range of failures: alternator, fuel pump, belt, etc. So for most trips, no schlepping around a bunch of tools and parts. Since these failures are so rare, this approach has worked well for me.

I have found maintaining a ~150k-200k fleet to be far cheaper than continually replacing with lower mileage cars when you get to 150k etc. The key, of course, is to be extraordinarily careful about which used car you buy. Don't get surprised by problems a year after you buy it.

[erikv11]

Another trick if one has to go home with no time to change alternator...when dealing with this issue to avoid towing halfway through.

Buy a new battery ($120 at Costco for Interstate)...charge it well, then make the trip, approx 45 min later swap battery.
At next stop, charge both batteries etc.

Anyway, a few cycles of discharge will significantly shorten the life of the battery...

PS: another option is to carry a spare used alternator in the trunk for long trip. Go to junk yard or eBay and get an alternator ahead of time for let's say $35-$50. Bench test it first (AutoZone etc). Then bring it along for long trip. The money spent here is worth it considering the inconvenience of towing etc. Also, if and whenever you sell the car, you can always resell this used alternator on eBay etc. so you are not losing much money here.

Yep, we initially considered buying a new battery but quickly discarded the idea. We decided to discharge-recharge-and-ruin only one battery. Additionally, they (drivers of this car) could change a battery yes, but it's not a no-brainer activity for them like it is for most of us on the forum.

[jonesg]

you get more miles if you pull the AOC fuse from the rear panel, no sense running the haldex pump.
i drove mine 60 miles, it easily restarted when i got home.

[erikv11]

Yeah this car was easily starting even with very low battery charge. Ability to start up seems not very informative. Good tip on the Haldex pump.

[erikv11]

An update 5 months later: the battery seems to be unaffected by this episode.

We got the alternator replaced at a shop, with a Bosch rebuilt, and have been running it ever since on the same battery. The shop tested the battery and said it was fine, and it has performed well so far this winter even through the "polar vortex" days.

I do wish I could have replaced the alternator myself with a new Bosch, but oh well.