Like all things it depends.
-heat exposure
-amount of load

For example I've got an original alternator on a 2008 FXT with 260k miles still working perfectly.

 

@SmokeyBee, "It ain't broke, don't fix it!". I see more trouble on here from those that have replaced their alternator. My 2001 has 230,000 miles so way more than your 110k miles, and still on factory alternator.

My Subaru has spent it's entire life here in Texas, so it is exposed to heat big time. Load? Standard load.

It ain't broke, don't fix it.

 

Alternators aren't really a common failure item on Subarus. My 2011 Outback 3.6R still had its original alternator at 250k. Several other Subarus I've owned or maintained over the years all had their original alternators at 180k+, 220k+, etc. I think I may have replaced one alternator ever on a Subaru and that was because a bolt sheared off on the adjuster and I had another with a good adjuster and just swapped out the whole assembly. That alternator was working just fine, though.

 

I went over to the pick and pull junk yard and got a spare alternator and starter. Then I went through both; cleaning, inspecting, and lubricating where required. $40 each for OEM parts.

 

I sort of did what @donkpow did with my 2010 Impreza. It had a small squeak in one of the bearings when I bought it in late 2014.

I bought both bearings from my local dealer, I don't recall the price, but it was fairly cheap, I want to say under $20.

I pulled the alternator apart, this took some patience, as a couple of the fasteners were corroded in there pretty good. For a 4 or 5 year old car, it was pretty abused and neglected. You could say it had a hard 83,000 miles on it.

Then cleaned everything. Actually I had access to a bead blaster at the time, and removed all the oxidation and rust, then clear spray painted the aluminum and painted the middle black it so it would stay nice looking.

It went pretty well, but you'll need an impact to get the nut off to remove the pulley. And to reinstall it. Unless you want to risk damaging the pulley trying to hold it.

It still worked and looked brand new at 230,000 miles when I traded it in. It still had the original brushes, etc. Everything but the bearings.



If you don't have patience, or basic mechanical skills, I don't recommend a rebuild on your own. There are some semi fragile parts that won't survive...

 

I thought about going ahead and rebuilding my spares. Then I realized, they are only spares. I'll hold them in reserve until I need them, when I will swap them out and rebuild the failed part.

 

Well it seems fairly unanimous...what about the starter? Same answer?

@Black21Limited I have the skill but not the patience. Never rebuilt an alternator but I rebuilt a starter for the first and last time in 1987, haha.

 

My alternator on my 2008 was replaced in 2016 at 50,000 miles. I had not noticed any symptoms but I guess the battery would eventually grow weak.

Replaced alternator (not charging well under load).	574.96​
Replaced battery with Interstate, old one failed load test.	129.98​

 

@SmokeyBee,
If you're going to fix everything because it might break, you're going to spend a heap of money. Even brand new cars have failures sometimes.

 

Bearing (s?) on our 2000 got noisy around 160k miles, so I replaced them for way less than the cost of a replacement alternator. I think only one (drive end) was going bad, but if I'm going to go to the trouble of tearing it down I'm going to replace both for the small additional cost of the second bearing. I'm experienced in electric motor repair, and have the tools, so bearing replacement is a no-brainer for me. I thought maybe the brushes would be due for replacement, but they were less than half worn. Have something like 180k on the car now and the alternator and starter are both fine, and this is in southern California with some warm temps, but just the stock electrical load. BTW, if you order an alternator brush by the factory number, that is exactly what you get - one brush! Not a set of two, like you would probably need for a rebuild. You can probably figure out how I know this now . . .

 

I purchased a spare alternator & starter for my 2005 & 2012 as soon I my ownership started as there are a number of posts on this forum about failures. I carry them with me on long trips.

You can fit the larger output 100A alternator from WRX & Liberty to the EJ engine as they are basically the same. As far as I know the alternators on the FB engines are the same.

The alternators are made by Mitsubishi. So that the rotor can fit into the housing the rear bearing is of smaller diameter than the diameter of the copper ring that the brushes contact. To handle the load it is also a double row bearing. This bearing is so small it is the one most likely to wear in my opinion. Use a long screwdriver or purchase a proper automotive stethoscope and listen to the bearings and the rear will be the noisey one. The Bosch system is much better as the regulator with brushes are removed first and this allows for a larger rear bearing.

As the starter motors use permanent magnets there is no soldering to replace the brushes. You just fit a new brush set with holder and bolt it in. The worst part is cleaning the motor.

 

Errata. Following from what I said above. I did not mean the FB engine alternators are the same as the EJ engine. What I meant was that it appears the FB engines all use the same output alternator.

 

@SmokeyBee,

Alternators with integral voltage regulars are often replaced "by a shop" because the voltage regulator failed. It is often cost effective and prudent to sell a new or rebuilt/refurbish alternator to their customers rather than replace the voltage regulator by itself. Worried about your charging system failing on a long trip? Have your charging system and battery tested with and without a heavy load to check for weaknesses.

If your local community college has auto shop classes sign up and do the work yourself. It's fun.

 

@SmokeyBee 20 years