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Discussion Starter · #1 · (Edited)
In the five years since I bought my 2003 outback from the dealer with 70k miles, I have had to replace the alternator 14 times along with 4 new batteries. The alternators have been purchased new under warranty from Autozone and Napa. The second most recent one failed after only 2 months. Most have slowly died, where I have to jump it every few starts to it dying while idling at a red light. I've had multiple shops, mechanics and electrician ex-boyfriend go through the car and nobody can find anything wrong with it. It has the factory stereo and no other aftermarket enhancements, so I know it's not a poor wiring install.
The check engine light has been on two years, the code P420 for the catalytic converter being the most frequent reading among several. I replaced the o2 sensors, but no change. The seatbelts light intermittemly comes on and off, although the belts were fixed before I bought the car, supposedly.
Last week the tensioner pulley seized up and broke the belt and fried the alternator (surprise, surprise). I told the dealership again about the alternator issues and they seem to think that a $500 OEM alternator will be the solution.
I am morbidly looking forward to the next time I have it towed back when this factory one dies next, just so they believe me about the previous 14. Something killed the original one along with all the others and I doubt that they will actually investigate until the new one dies and they are forced to reexamine on their dime.
Hopefully the new OEM is the magic solution! In the meantime, has anyone had similar issues and how did you fix? I suspect there's a short in one of the ground wires, but don't know how, where, or what to test. I'm just sick of getting stranded in less-than-hospitable places (the middle of the Navajo reservation at 3am during the covid lockdown most recently) and having to carry an extra alternator wherever I go. I love this car, a side from these setbacks, and have to find a solution as buying a new vehicle isn't in my near financial future.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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H6 or H4 ? they have different alternators and it matters. Some pasrts stores do not make good distinction between them.

you may have a poor ground connection somewhere, or possibly bad battery cables.. ANY 17 year old vehicle could have issues like this, and the problem is being perpetuated with aftermarket alternators, they are widely known to be a poor risk.

You would better served with a used OEM, or, perhaps, take a used OEM to a local rebuilder, have them go thru it, and will be better than new aftermarket.

you can also check Maniac electric or DBelectric for well-respected options.

as for other problems, check the 'sticky' threads at the top of the Gen 2 Forum.
 

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Outback 2011 3.6R Premium
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Genuine Subaru alternators are known for their quality and typically travel around 180,000 miles before needing to be rebuilt. Aftermarket alternators are known to not be as good as a genuine Subaru alternator (as you have found).

If you have a faulty alternator the most likely thing to fail will be the battery so I am not surprised that you have had four battery failures.

As Lucky Texan advises a second hand alternator from a car dismantler is often a better choice than an aftermarket alternator and if you have a H6 engine you need a specific alternator and aftermarket alternators are known to not be compatible with the H6 engine.

Hopefully your new genuine Subaru alternator will be the solution to your five years of ongoing problems.

Seagrass
 

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2006 Subaru Outback Wagon 2.5L XT Limited
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I would stick with OEM alternators or Denso Alternators. With my 1990 subaru Legacy, I had burned through around 3 alternators within a month period of time. Just to give you a run down. Subaru uses a lot of Denso electric parts on their cars. Anyways with that being said, my 90 lost its original alternator due to age and me adding in a subwoofer in the back. Then I took the car to my local mechanic shop, which they've installed a Bosch Rebuilt Alternator. Within two weeks, that alternator died. I had it replaced under warranty. Another two weeks, same thing. After about the 3rd alternator, I finally convince the owner of that shop to put in a Denso alternator. After that no more alternator issue. I still ran the subwoofer amp in the back doing the whole time, but only when I was at cruising speed. Matter of fact, during this time, I studied the Alternator specs in the service manual and learn extremely fast, cars are designed to be moving at all times, not sitting at a traffic light, in-gear, with all of the accessories running, specially during the summer time. All of this loads down the alternator, because of this I don't run my wiper blades when siting at a traffic light. The second the light turns green, (if it is raining) I turn the wiper blades back on. I mainly use the one-swipe wiper switch to activate the wipers. I tested an experiment, I connected an Amp meter and performed a load down test while at idle, with normal accessories on; a/c on, wiper blades on, car running and in gear, foot on brake, both radiator fans on, and no sub amp in the back. I was pushing 70amps. The alternator inside the car was only 70 amp alternator. The subwoofer only drew 5-10amps.

Batteries, Back in the old days, 60s and 70s batteries were shipped without battery acid in them. They could say on the shelf for long periods of time because of this. Now-a-days, they are shipped with Battery Acid already in them from factory. By the time you install that battery in your car, that battery is no longer fully charged. Side Note, lithium ion Batteries cannot be shipped on a plane fully-charged within/to/from USA. A law back in the 60s prevents this from happening. The battery chemistry can ignite in to a fire in mid-air. So to get around this, they ship the batteries half-charged on planes. This is why when you get a brand new phone/laptop/etc, you have to charge it as soon as you get the device.

Since car batteries are not fully charged when you install them into the car, and alternators only provide as low as 12amps at idle, the second the alternator starts to charge the battery you are now straining the alternator to charge the battery and drive the car. Like I said, 12 amps at idle, Car batteries can take as much as 7 amps to charge, so that leaves you with 5 amps to run the car. Also it takes a car battery as much as 5 hours to fully charge. Most people don't want to wait 5 hours to charge the battery before installing the battery in the car. So the fact that you blew through 14 alternators and 4 new batteries, gives me a clue that maybe the alternators died because the batteries was never fully charged before them being installed into the car. Another clue, is the manufacture of the alternator. Like I had said, Denso/OEM are very good brand for subaru. I had issues with bosch alternators, my issue went away when I switched to Denso, because of this I avoid Bosch products completely.
 

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I love this car, a side from these setbacks, and have to find a solution as buying a new vehicle isn't in my near financial future.
How does one love a car that keeps letting them down? Makes no sense to me.

Have the battery cables been replaced? Sometimes they become corroded on the inside while appearing find on the outside.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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How does one love a car that keeps letting them down? Makes no sense to me.

Have the battery cables been replaced? Sometimes they become corroded on the inside while appearing find on the outside.
'the car' may have let him down with the original alt failure - not sure, it could have been purchased with a poorly rebuilt alt that was put in by a prev. owner. Certainly seems to me parts retailers could have let him down several times.
 

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'03 outback limited, '01 Outback Limited, '01 Legacy L wagon, '96 Legacy Brighton wagon
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Are there available any alternators that have a higher output? Good quality, of course.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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Really need more information on car model/trim level, engine etc.

Also, were the returned alternators bench tested -- hard to imagine the stores replacing five or more in short order without verifying -- and if so, what were the tests results saying?

What troubleshooting was done over the years?

Was the car bought from a Subaru dealer, and did the deal do any troubleshooting?
 

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2005 Outback Wagon 3.0 L.L. Bean
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Grounding system. Piggyback some larger gauge ground wires over the existing main ones. Make sure you clean to bare metal existing mounting points before adding the reinforcements.
Batt - to strut tower. Strut tower to top rear of engine. Top rear of engine to firewall. Bottom of engine has one on each head to framerail. These premade cables make it easy and are cheap. https://www.autozone.com/batteries-...HraKGT3KqhhovG-anKRoCwtYQAvD_BwE&gclsrc=aw.ds
An additional large gauge FUSED cable from ALT+ to BAT+ to complete the upgrade.
My bet is you have very high resistance somewhere due to corrosion. If all the grounds are still intact then a cleaning and re-mount to the grounds and alt cable may be all that is needed.
 

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2006 Subaru Outback Wagon 2.5L XT Limited
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Are there available any alternators that have a higher output? Good quality, of course.
Yes,
 

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'06 B9, '10 FXT Prem, '11 OB 3.6R Ltd, '13 FXT Ltd, '14 OB 3.6Rs Ltd, '15 WRX Ltd
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Yes,
I have one... I didn't have alternator issues, I just needed more juice in my 99 OB. A little spendy, but cheaper than a new OEM. Yes, they do produce a LOT more amperage. Been on for 2+ years with no issues. Direct drop in.
 
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1999 Outback Limited Manual EJ25
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My H4's alternator died at around 230,000 miles, I got a replacement from a wrecker that specialises in Subaru. It was surprisingly cheap, about 1/8th the cost of a reputable aftermarket replacement. Have only done 25,000 miles since but haven't had a problem. When I called the wrecker their first and only question was about the number of pins on the connectors.

An easy way to keep an eye on the performance of your alternator is with a plug-in LED meter like this: 12V-24V Digital LED Display Car Battery Voltage Gauge Voltmeter Tester Detector | eBay
 

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I seem to remember the Impreza OB used the 90A Alternator while the Legacy OB used the 120A...they both fit the 2.2. and 2.5 so a lot of aftermarket companies show a 90A as a fit for the Legacy and its cheaper but burns out faster...a shop that doesnt know this might buy you the Impreza alt to increase their profit....
 

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In the five years since I bought my 2003 outback from the dealer with 70k miles, I have had to replace the alternator 14 times along with 4 new batteries. The alternators have been purchased new under warranty from Autozone and Napa. The second most recent one failed after only 2 months. Most have slowly died, where I have to jump it every few starts to it dying while idling at a red light. I've had multiple shops, mechanics and electrician ex-boyfriend go through the car and nobody can find anything wrong with it. It has the factory stereo and no other aftermarket enhancements, so I know it's not a poor wiring install.
The check engine light has been on two years, the code P420 for the catalytic converter being the most frequent reading among several. I replaced the o2 sensors, but no change. The seatbelts light intermittemly comes on and off, although the belts were fixed before I bought the car, supposedly.
Last week the tensioner pulley seized up and broke the belt and fried the alternator (surprise, surprise). I told the dealership again about the alternator issues and they seem to think that a $500 OEM alternator will be the solution.
I am morbidly looking forward to the next time I have it towed back when this factory one dies next, just so they believe me about the previous 14. Something killed the original one along with all the others and I doubt that they will actually investigate until the new one dies and they are forced to reexamine on their dime.
Hopefully the new OEM is the magic solution! In the meantime, has anyone had similar issues and how did you fix? I suspect there's a short in one of the ground wires, but don't know how, where, or what to test. I'm just sick of getting stranded in less-than-hospitable places (the middle of the Navajo reservation at 3am during the covid lockdown most recently) and having to carry an extra alternator wherever I go. I love this car, a side from these setbacks, and have to find a solution as buying a new vehicle isn't in my near financial future.
Book this car on a flight to the moon!
 

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2007 Subaru Outback 2.5L Basic
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H6 or H4 ? they have different alternators and it matters. Some pasrts stores do not make good distinction between them.

you may have a poor ground connection somewhere, or possibly bad battery cables.. ANY 17 year old vehicle could have issues like this, and the problem is being perpetuated with aftermarket alternators, they are widely known to be a poor risk.

You would better served with a used OEM, or, perhaps, take a used OEM to a local rebuilder, have them go thru it, and will be better than new aftermarket.

you can also check Maniac electric or DBelectric for well-respected options.

as for other problems, check the 'sticky' threads at the top of the Gen 2 Forum.
Sorry to hear about your alternator issues.
H6 or H4 ? they have different alternators and it matters. Some pasrts stores do not make good distinction between them.

you may have a poor ground connection somewhere, or possibly bad battery cables.. ANY 17 year old vehicle could have issues like this, and the problem is being perpetuated with aftermarket alternators, they are widely known to be a poor risk.

You would better served with a used OEM, or, perhaps, take a used OEM to a local rebuilder, have them go thru it, and will be better than new aftermarket.

you can also check Maniac electric or DBelectric for well-respected options.

as for other problems, check the 'sticky' threads at the top of the Gen 2 Forum.
Sorry to hear about your alternator issues. I recently had a new unit fail on my 2007 4cyl OBW which I bought in July. I felt obligated to chime in when '1 Lucky Texan' offered DB Electric as a good solution. This one I purchased from them lasted 3 months. It has a 1yr warranty and I'm working with them for a refund, but I can't recommend them with a clear conscience. I like the idea of getting an OEM used one, and thanks to an abundance of available salvage yard parts, you wouldn't have to look very hard. Best wishes.
 

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2006 Subaru Outback 2.5i
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I’m not sure if you’ve checked it, but did the original ground strap rot off? My 2006 went through 2 alternators in a year, and it turns out that the oem ground strap had rotted off, causing the ground to have high resistance. You should be able to see it if you look down in the engine bay on the right side, near the battery. It’s like $5 for a universal one. Also as a side note, my battery (which is going on 6 years old) a Sears diehard platinum, kept the car going both times for well over 2 hours with accessories running. Good luck!
 

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In the five years since I bought my 2003 outback from the dealer with 70k miles, I have had to replace the alternator 14 times along with 4 new batteries. The alternators have been purchased new under warranty from Autozone and Napa. The second most recent one failed after only 2 months. Most have slowly died, where I have to jump it every few starts to it dying while idling at a red light. I've had multiple shops, mechanics and electrician ex-boyfriend go through the car and nobody can find anything wrong with it. It has the factory stereo and no other aftermarket enhancements, so I know it's not a poor wiring install.
The check engine light has been on two years, the code P420 for the catalytic converter being the most frequent reading among several. I replaced the o2 sensors, but no change. The seatbelts light intermittemly comes on and off, although the belts were fixed before I bought the car, supposedly.
Last week the tensioner pulley seized up and broke the belt and fried the alternator (surprise, surprise). I told the dealership again about the alternator issues and they seem to think that a $500 OEM alternator will be the solution.
I am morbidly looking forward to the next time I have it towed back when this factory one dies next, just so they believe me about the previous 14. Something killed the original one along with all the others and I doubt that they will actually investigate until the new one dies and they are forced to reexamine on their dime.
Hopefully the new OEM is the magic solution! In the meantime, has anyone had similar issues and how did you fix? I suspect there's a short in one of the ground wires, but don't know how, where, or what to test. I'm just sick of getting stranded in less-than-hospitable places (the middle of the Navajo reservation at 3am during the covid lockdown most recently) and having to carry an extra alternator wherever I go. I love this car, a side from these setbacks, and have to find a solution as buying a new vehicle isn't in my near financial future.
My wife recently bought a 2006 Outback with 109,000 miles. Shortly we were getting the P420. Shop looked it over and said it was neither the catalytic convertor nor the O2 sensors but a power steering fluid leak that was getting on the converter and causing it to overheat. Replaced the power steering pump and have had no further issues with that. (But we have had the transmission and engine replaced, one A-frame and one axel; we have finally realized that we are restoring the vehicle).
 

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2020 OB Limited, Titanium & Magnetite Grays
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I recall reading similar issues caused by high resistance electrical connection(s). This also seems to be the theme throughout these responses. The one that standsout is a high ground resistance hidden somewhere.

As for battery life, I have a battery tender with a plugin connection running through the grills of two vehicles. This has a nice low charge using a max of 2A. During the holiday season Costco has them for a low price markdown. I also have a larger charger that can be limited to a max 10A which is automatically adjusted. I use either of these chargers on my vehicles about once every 2 weeks, needed or not. Last battery I did this with was going on about 7 years old when I sold the car. It still tested to be good at the time the vehicle was sold.
 

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Check here for a good quality premade grounding kit at a very reasonable cost. Old subies are known for ground issues.Very easy to install and will hopefully help keep your next alternator alive. Just put one on my old 2001 Impreza I'm restoring

 
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