Alternator Rebuild as Preventative Maintenance?

I recently had a failed alternator rebuilt for a vehicle with 138,000 miles on it Another vehicle I maintain 175,000 miles on it with the original alternator. Because the car is used by a college student who travels 250 miles between shcool and home several times a year, I was thinking of pulling the alternator and having it rebuilt as preventative maintenance. Is there any merit to doing this, or am introducitng the ptotential for self-made problems in an alternator that is currently functional?

I am surprised it lasted that long. I prefer to put in new versus a rebuilt alternator. it seems there have been a higher failure rate with rebuilt alternators in my opinion.

Alternator Repair and Replacement Options

Buyers are sometimes confused by the three “Rs” when it comes to getting an alternator fixed: repaired, rebuilt and remanufactured. To add to the confusion, some “experts” will say there is no difference between a rebuilt and a remanufactured part. This is not true . Each term indicates an increasing level of sophistication in the ability to restore a broken alternator and the reliability of the end product.


Repairing an alternator means that whatever parts are malfunctioning are replaced. A skilled repairperson might also replace parts that are near failure. This option can be the least expensive for the vehicle owner depending on the cost of the parts that need replacement. Only replacing a part or two in an alternator that has already failed may be no more than a temporary fix.


Rebuilding an alternator is a more involved process. The alternator is dismantled and inspected. Internal electrical and electronic components are tested. Parts that are known to have a relatively short life may be replaced without testing. Although a rebuilt alternator sounds comparable to a remanufactured or a new alternator in terms of reliability, everything depends on the skill and standards of the individual technician who performs the work.


Remanufacturers follow strict guidelines and procedures. They replace the voltage regulator, diodes, brushes and any other part that has failed or is likely to fail. Their testing equipment is state-of-the-art. They restore an alternator to original equipment manufacturer standards of operation. A Factory Authorized Remanufacturer is best in class among remanufacturing facilities and offers the longest guarantee for the product. They even incorporate design improvements made since the alternator was originally manufactured.

But I would still go with a new one. but, that’s just me.

There is a never ending list of what ifs, alternator, fuel pump, wheel bearings, radiator, condenser, ball joints, control arms, starter motor, brake lines, coolant hoses, enough to make one crazy, use it till it it breaks is what I do, but I also throw in rear diff fluid, transfer case fluid, auto trans fluid, coolant as regular maintenance items.

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I used to have an auto electrical shop that would rebuild your generator, alternator or starter for the same price as a cheap rebuilt but you got a better product. Since he closed, I don’t know of any replacement place. The cost of doing business is so high today, I don’t think it would be a profitable venture.

After being disappointed in NAPA new and rebuilt, my last one was Delco. Never had a problem because they replace about everything. I don’t have that car anymore so don’t know but my Pontiac has the original GM Delco with 160K on it. I’ve been thinking the same thing.

In the old days I would rebuild mine about every 70,000 as a preventative measure. I’d do the regulator, diode trio, brushes, and either or both front and rear bearings. Never had one fail but back then the parts were about $25 and you could just unbolt everything. The last one I tried, stuff was crimped together and not really user friendly.

I would say that this plan to replace or rebuild the alternator as “preventative maintenance” makes about as much sense as replacing the head gasket or having the transmission rebuilt as “preventative maintenance”. There is no reason to believe that the alternator will fail at a specific mileage, unless abused–for example by an overtightened belt–and there is no reason to believe that the repair or replacement will be any more durable or long-lived than what you already have. I would just continue to do the manufacturer-recommended maintenance on this vehicle, and set aside money for the eventual unexpected repair.

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Maybe but based on my sample of 3 1/2 million miles, they don’t usually fail at a convenient time, and they are reasonably cheap (or were anyway). I was on my way to a funeral 200 miles away when my one year old NAPA went. 30 miles from home, ended up swapping it out in the NAPA parking lot.

Before I would rebuild/replace the alternator as preventive maintenance, I would replace the crank sensor.

Crank sensors fail far more often than alternators.

When crank sensors fail, you could end up stranded.

When the charging system fails, the reserve capacity of the battery will at least get you to a place for repairs.



I’d say you might be doing the above. If there was absolutely no chance the rebuilder might screw something up, make a mistake, or use an inferior part in there, I’d say go for it. Unfortunately, I don’t think the rebuilt alternator is guaranteed to last longer than the original one. Besides, if you proactively replace the alternator, the starter will automatically fail one week later. I’m kidding, but that would be my luck!

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Thanks for the thoughtful responses. Based on weekend-warrior’s response in post #3 above, the electric shop repaired my alternator, not rebuilit it. The tech said the diodes were burned so he replaced the rectifier bridge and also the clutch pulley which was also faulty. He charged me $65 for that service. I would have preferred a remanufactured unit that weekend-warrior described. Before I got the alternator serviced, I read a lot of advice that an alternator/starter electric shop is the way to go when an alternator goes bad, I must admit I have buyer’s remorse for not having gone with a new or re-manufactured unit that would have new bearings, since bearings seem like an item that will eventually fail. Or specified that the repair included replacement bearings…

That 250 mile highway drive that my daughter makes to school includes a section of highway that is in a rural area with few exits. That, and Wisconsin winters were what prompted me to ask about preventative alternator service. Probably the only worry-free option is a new vehicle, but that is not financially feasible for her or me.

Thanks again

Checking Rockauto, new ones are fairly cheap ($150) and @Tester may be right and worth the $13 for a crank sensor.

Yeah had to replace a fuel pump in a NAPA parking lot at 18 degrees, but your post brings up the point new parts can fail also!

A new OEM alternator would have been $235, pretty much the same price as the remanufactured ones from the parts stores; Rock Auto sells a new alternator by TYC for $180. I am just going to leave the $65 repaired alternator in the car. When it fails, I can move on to something else.

RE: NAPA I always thought their parts were a cut above other parts stores. I suppose anyone can have a dud.

I am surprised that they could obtain the parts this cheap, the over-run clutch should have a retail price of $65.

Well not just one but at least three, and I bought new not rebuilt. After the last one, I just got a Delco and chucked the NAPA one.

new cars can break down, too. Best advice is to make sure she has a charged up cell phone before making the drive. AAA membership can’t hurt, either. Towing, some roadside assistance, fuel, lockouts, etc. can be covered.


One problem with replacing an alternator when it isn’t broken, the replacement unit may actually be worse than the existing one. This is especially true for aftermarket parts. An alternative, if your student is capable of replacing the alternator themselves in event of a breakdown, carry a spare alternator in the trunk with the required tools.

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She won’t be changing any parts on her own. She has no interest in automobile maintenance. Neither does my college age son. I have them schooled in basic preventative maintenance like fluid levels and tire pressure, but that is the limit of their interest in cars.

They will probably spend at least the second half of their driving lives in electric vehicles. My uneducated guess is that vehicles propelled by electric motors will have far fewer maintenance requirements, which will be helpful for non-maintenance minded car owners like my kids.

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Folks I know owning electric vehicles tell me that is definitely a major advantage. No liquid cooling system to maintain for example. No exhaust system for thieves to steal cat’s from. And a huge advantage in some states, no emissions testing. I speculate however that electric’s won’t hold up for long periods of time as well as well-maintained gasoline cars. I don’t see many electric car owners keeping their cars for 30-50 years, like I have.