Alternator/Starter Life Expectancy
- Thread starter 4camv8
- Start date
- Location
- brooklyn, ny
I replaced my starter at almost 70k, but that in no way indicates that yours couldn't last to 150k+ & is no indication as to life expectancy really... for the most part they should both be fine till 100k & more...
Good to know, with today's alternators not really giving you any warning prior to failure and just shutting everything down when they fail, I figured I might replace in a preemptive manner... Guess I'll be patient.
Turbocad6, stunning ride, wish you had a shop down south!
Turbocad6, stunning ride, wish you had a shop down south!
160K and no starter or alt yet for my 04 "knocks on wood"
- Location
- Miami
- Car
- 2004 Infiniti FX35 Supercharged
Replaced both this year. 10 years not bad IMO.
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• •
- Location
- Atlanta, GA
- Car
- 2007 FX35
Not much point in changing them proactively. There are typically warning signs before they fail, so it's not going to be a sudden stranding. If your battery isn't charging right, check your alternator. If your car isn't starting correctly, then you can diagnose if it's the starter or not.
SCY7H3
Member
- Location
- Toronto, Ontario
- Car
- 2012 FX35S AWD
Hey Guys, figured I'd give you some insight on this since I've had some great experience in this area and might be useful to some of you.
Usually starters/alternators fail prematurely because of battery issues. You should check your battery with a battery load tester to make sure that the battery is healthy.
One of the main reasons why alternators fail is because the battery isn't holding a good enough capacity to allow the alternator to work in a normal state. What happens is that the voltage regulator in the alternator rather than working at say 50% capacity, its now working at 100% capacity constantly and with the heat of the engine wears down the voltage regulator until it fries. The battery will have enough juice for 1 to 3 starts but then you'll see a rapid decline in power which then starts killing the starter (i'll get to that point later).
You won't see an issue until either the battery completely dies or the alternator's voltage regulator dies.
One of the main reasons why starters fail is because yet again the battery was not holding a good enough charge. The starter needs a huge amount of current to crank the engine. Most of that current goes to the starter itself, a partial amount goes to the electromagnet/relay inside the starter. If there's not enough current, two things happen. The starter isn't getting enough power to easily turn over the engine thus creating heat in the wound stator and the electromagnet doesn't have enough power to keep the relay engaged 100% so it creates arching at the copper plates.
You normally don't see this issue because as the health of a battery slowly declines, the sound of the starter slowly changes indicating a change or issue. And as this slowly progresses, you will only find out when either the battery, starter or alternator gives up. Then you're at a total loss.
I've had this happen in two different vehicles and it wasn't always a total loss but that depends on what gave up first, the battery or the rest.
So on one vehicle, the battery was dying, but it wasn't noticeable because the alternator would keep it at best of its performance. When a battery's capacity diminishes, it actually charges faster. The only way you can see it's capacity is either using a charger that shows capacity as it charges or a battery load tester.
As the battery slowly progressed to it's death, the alternator was getting beat up running at 100% capacity at all times. The starter's relay was arching creating holes in the copper plates.
The issue was only apparent when the car would die while idling at a light. Long story short, half the voltage regulator in the alternator fried limiting the alternator to 50% of its peak power, so at idle, it was not enough to keep the battery and all the electronics alive. The battery died because it wasn't getting charged and the starter needed a new relay (copper plates) because they were perforated from all the arching.
In the end, I needed a new battery, I rebuilt the starter and the alternator for what could have been just a battery if I checked it yearly.
Spend the money, get a battery load tester, they're usually on sale and are cheaper than getting all three things replaced/repaired.
Usually starters/alternators fail prematurely because of battery issues. You should check your battery with a battery load tester to make sure that the battery is healthy.
One of the main reasons why alternators fail is because the battery isn't holding a good enough capacity to allow the alternator to work in a normal state. What happens is that the voltage regulator in the alternator rather than working at say 50% capacity, its now working at 100% capacity constantly and with the heat of the engine wears down the voltage regulator until it fries. The battery will have enough juice for 1 to 3 starts but then you'll see a rapid decline in power which then starts killing the starter (i'll get to that point later).
You won't see an issue until either the battery completely dies or the alternator's voltage regulator dies.
One of the main reasons why starters fail is because yet again the battery was not holding a good enough charge. The starter needs a huge amount of current to crank the engine. Most of that current goes to the starter itself, a partial amount goes to the electromagnet/relay inside the starter. If there's not enough current, two things happen. The starter isn't getting enough power to easily turn over the engine thus creating heat in the wound stator and the electromagnet doesn't have enough power to keep the relay engaged 100% so it creates arching at the copper plates.
You normally don't see this issue because as the health of a battery slowly declines, the sound of the starter slowly changes indicating a change or issue. And as this slowly progresses, you will only find out when either the battery, starter or alternator gives up. Then you're at a total loss.
I've had this happen in two different vehicles and it wasn't always a total loss but that depends on what gave up first, the battery or the rest.
So on one vehicle, the battery was dying, but it wasn't noticeable because the alternator would keep it at best of its performance. When a battery's capacity diminishes, it actually charges faster. The only way you can see it's capacity is either using a charger that shows capacity as it charges or a battery load tester.
As the battery slowly progressed to it's death, the alternator was getting beat up running at 100% capacity at all times. The starter's relay was arching creating holes in the copper plates.
The issue was only apparent when the car would die while idling at a light. Long story short, half the voltage regulator in the alternator fried limiting the alternator to 50% of its peak power, so at idle, it was not enough to keep the battery and all the electronics alive. The battery died because it wasn't getting charged and the starter needed a new relay (copper plates) because they were perforated from all the arching.
In the end, I needed a new battery, I rebuilt the starter and the alternator for what could have been just a battery if I checked it yearly.
Spend the money, get a battery load tester, they're usually on sale and are cheaper than getting all three things replaced/repaired.
sungunner
Member
- Location
- Central NJ
I have just reached 201,000 with my 2003 FX45. Not only has it been the most fun car I've owned, but its been one of the most reliable. I have detailed my repair history elsewhere on the forum, but wanted to respond to the starter and alternator question.
I replaced my battery with a DieHard a few years back, not sure the actual mileage.
I just replaced the starter at approx 199,000 miles, after it failed to start for a half hour or so, then finally powered up. Replaced it with an Autozone Duralast reman starter. Admittedly, it doesn't have the same fast cranking power that the original had, but it does the job.
I haven't change the alternator yet. but rather than press my luck I was considering whether I want to pre-emptively do so. Since I am between jobs, I would probably not buy an Nissan/Infiniti $$$ unit. Anyone here install a non-Nissan unit that they like and performs quietly and generates sufficient clean power? I've helped people replace their brushes and regulators on other cars to extend alternator life, but don't want to get into the soldering, etc for this car.
I replaced my battery with a DieHard a few years back, not sure the actual mileage.
I just replaced the starter at approx 199,000 miles, after it failed to start for a half hour or so, then finally powered up. Replaced it with an Autozone Duralast reman starter. Admittedly, it doesn't have the same fast cranking power that the original had, but it does the job.
I haven't change the alternator yet. but rather than press my luck I was considering whether I want to pre-emptively do so. Since I am between jobs, I would probably not buy an Nissan/Infiniti $$$ unit. Anyone here install a non-Nissan unit that they like and performs quietly and generates sufficient clean power? I've helped people replace their brushes and regulators on other cars to extend alternator life, but don't want to get into the soldering, etc for this car.