Should I proactively replace my stock alternator at 200K miles?

CBR.worm

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'06 Infiniti G35 w/ 200K miles. I am resealing the timing cover and replacing the water pump and associated parts for the first time, due to a small oil leak at the bottom edge - it's not dripping yet, but it is getting the front of the motor grimy and I'm sure it will get worse. While I have the alternator off, should I replace it with a new OEM one?

While the alternator is off the car, it would be very easy to replace. This car isn't worth much, but it is fun and in good shape. I plan to drive it until something catastrophic happens, or until it becomes unreliable. I'm replacing the idler pulleys, the radiator, and other pieces that I had to remove to get the timing cover off, also the primary timing chain, chain guides, crank sprocket, tensioner, and gallery gaskets. I read so many horror stories on the internet about the VQ35 tensioner and guide issues and gallery gaskets, but I have no visible wear on anything other than the crank sprocket. No signs of impending doom. I've got the new OEM parts, so I'm going to put them on.

I expect to do a couple of cross-country trips this summer, and while I don't want the car to ever leave me stranded, it would be worse if I was thousands of miles from home. I don't expect the OEM alternator to fail in the next 10 or 20K miles, but it might and I would prefer to not have to touch the serp. belt-driven components again for a long time.

I don't know what the lifespan on these is. It is a Mitsubishi branded alternator. I would think that I have probably used up most of its life, but I really don't know. The mechanical parts on this car seem to last forever.
 
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'06 Infiniti G35 w/ 200K miles. I am resealing the timing cover and replacing the water pump and associated parts for the first time, due to a small oil leak at the bottom edge - it's not dripping yet, but it is getting the front of the motor grimy and I'm sure it will get worse. While I have the alternator off, should I replace it with a new OEM one?

While the alternator is off the car, it would be very easy to replace. This car isn't worth much, but it is fun and in good shape. I plan to drive it until something catastrophic happens, or until it becomes unreliable. I'm replacing the idler pulleys, the radiator, and other pieces that I had to remove to get the timing cover off, also the primary timing chain, chain guides, crank sprocket, tensioner, and gallery gaskets. I read so many horror stories on the internet about the VQ35 tensioner and guide issues and gallery gaskets, but I have no visible wear on anything other than the crank sprocket. No signs of impending doom. I've got the new OEM parts, so I'm going to put them on.

I expect to do a couple of cross-country trips this summer, and while I don't want the car to ever leave me stranded, it would be worse if I was thousands of miles from home. I don't expect the OEM alternator to fail in the next 10 or 20K miles, but it might and I would prefer to not have to touch the serp. belt-driven components again for a long time.

I don't know what the lifespan on these is. It is a Mitsubishi branded alternator. I would think that I have probably used up most of its life, but I really don't know. The mechanical parts on this car seem to last forever.

Keep this up you won't have the chance for a catastrophic event...other hand you could buy a e.bay Denso reman keep it in the trunk and sell it if not used.
 
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'06 Infiniti G35 w/ 200K miles. I am resealing the timing cover and replacing the water pump and associated parts for the first time, due to a small oil leak at the bottom edge - it's not dripping yet, but it is getting the front of the motor grimy and I'm sure it will get worse. While I have the alternator off, should I replace it with a new OEM one?

While the alternator is off the car, it would be very easy to replace. This car isn't worth much, but it is fun and in good shape. I plan to drive it until something catastrophic happens, or until it becomes unreliable. I'm replacing the idler pulleys, the radiator, and other pieces that I had to remove to get the timing cover off, also the primary timing chain, chain guides, crank sprocket, tensioner, and gallery gaskets. I read so many horror stories on the internet about the VQ35 tensioner and guide issues and gallery gaskets, but I have no visible wear on anything other than the crank sprocket. No signs of impending doom. I've got the new OEM parts, so I'm going to put them on.

I expect to do a couple of cross-country trips this summer, and while I don't want the car to ever leave me stranded, it would be worse if I was thousands of miles from home. I don't expect the OEM alternator to fail in the next 10 or 20K miles, but it might and I would prefer to not have to touch the serp. belt-driven components again for a long time.

I don't know what the lifespan on these is. It is a Mitsubishi branded alternator. I would think that I have probably used up most of its life, but I really don't know. The mechanical parts on this car seem to last forever.
Normally I would say no just leave it until it fails but this one is a bit of PITA to do in a parking lot and then trying to find one on the spare of the moment. 200k in my experience is a good run for an alternator, taking one on a cross country trip would be like buying a plane ticket for next year for a 94 year old.
There is no new OE, they are a reman albeit a higher quality one not some Cardone autozone crap and about $315, not bad if don't have a local rebuilder.



 
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The answer to replacing an alternator is the amount of time needed for the fix and how far away from home does the vehicle travel.
My daughter has a 2003 Ford Escape V6 AWD. Her alternator failed at 98K miles and this job requires you to pull an axle, take the bolt out of the motor mount and use a come-along to nudge the engine forward getting access to the alternator R&R. Not a job that where you replace it with a chain-store "lifetime warranty". The alternator in my '97 F250 5.4 is factory and has 270K miles on it. I figure I'll run it until it fails to get my money's worth on it. :ROFLMAO: It takes very little time at all for a replacement, but again, I'm not going to go price shopping when it gets replaced.
 
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Normally I would say no just leave it until it fails but this one is a bit of PITA to do in a parking lot and then trying to find one on the spare of the moment. 200k in my experience is a good run for an alternator, taking one on a cross country trip would be like buying a plane ticket for next year for a 94 year old.
There is no new OE, they are a reman albeit a higher quality one not some Cardone autozone crap and about $315, not bad if don't have a local rebuilder.




This^^^

I haven't had many Alternator's fail on me, Did have a Denso fail on my 2010 Corolla around 100,000.

Late Nissans aren't known for easy Alternator access!
 
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I bought my car with over 200k, have been replacing any parts i can find cheap and install myself. Got a new acdelco gold for $30 and higher voltage, smoother idle.

I also found replacing the throttle body, coil pack and fuel pump helped things, while the internet says leave alone if working.
 

Sam_Julier

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Send it to Rayelco Generator in Lodi NJ for a rebuild or restoration. Their work is superb at a fair price.

I‘m not inclined to replace a part that is working well with a part of unknown ability. Just rebuild or restore it.
 
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CBR.worm

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Interestingly, it looks like my SUV uses the same alternator. So I could replace this one and have it standing by to be refreshed in case the FX50 needs one in the future. This is sounding more appealing.

Edit: or maybe it isn't the same. Scratch that.
 
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Should I proactively replace my stock alternator at 200K miles?​

no-just-no.jpg
 
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yes, bad starter, you can always hit it with a hammer. If alternator brushes go, you have no options. And if happens away from home, you'll need a tow.

you can check the old alternator's brushes by removing it. but by that point, you might as well put in a new/reman. alternator.

If brushes go it’s a very easy fix to get you home. Cut up a penny and install in front of the springs. It works every time.
 
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That's just the pulley and bearing. I'm not sure that will tell you if the brushes are shot.
And if you do hear bearing noise, it's probably time to replace it anyway.

I had one that made horrible bearing noises and I waited just one day too many to replace it..... The bearing seized and it totally stopped my engine, thanks to the serpentine belt! LOL I walked home that day...
 
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One of the mechanics at a Volvo specialist shop had the alternator fail on his 240 when he was a few hundred miles from home. He bought a new battery, ensured it was fully charged, then drove the car home during daylight hours with no fan, radio, etc running. He replaced the alternator when he got home. So he ended up with a new battery instead of paying someone to do a job he could easily do himself.

Being able to do this would depend on how the alternator was set up and which component had failed. A failed bearing and an alternator on the same belt as the water pump wouldn't be a good combination for example.
 
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One of the mechanics at a Volvo specialist shop had the alternator fail on his 240 when he was a few hundred miles from home. He bought a new battery, ensured it was fully charged, then drove the car home during daylight hours with no fan, radio, etc running. He replaced the alternator when he got home. So he ended up with a new battery instead of paying someone to do a job he could easily do himself.

Being able to do this would depend on how the alternator was set up and which component had failed. A failed bearing and an alternator on the same belt as the water pump wouldn't be a good combination for example.

I would not expect to drive a few hundred miles with no alternator. Maybe 30.
 
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I would not expect to drive a few hundred miles with no alternator. Maybe 30.
You'd be surprised. When my alternator died, I ordered a new one and then took my battery in and fully charged it. Drove over 40 miles to my mechanic who replaced it. Did the same, no vents, no radio the whole way. I was able to track the battery voltage and I can't remember how much it dropped but toward the end when I got close, there was still plenty of battery power left so I turned on the radio. Worse case at the time was that the battery dies and I just get a tow from AAA but that would have taken even longer.
 
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How far a car can be driven with no functioning charging system has a huge amount of variables.

The reserve capacity of a battery is the minutes it can provide 25 amps of load before battery voltage hits 10.5v.

But will the vehicle still run at 10.5v. Some will, some will not.

The reserve capacity minutes assume the battery is still healthy and Fully charged. So basically those minutes can be expected only when the battery is new and hot off charger.

How much amperage does any specific vehicle need to run the ignition and fuel pump and any other accessories? Big variables here.

A few years back my reman'd alternator failed 20 miles into a ~ 140 mile drive, at night. I noticed my voltage went from 14.7v with the battery accepting about 9 amps( so about 85% charged) , to 12.7v and delivering 27 amps to run the engine and lights and Hvac fan.

My group 31 TPPL agm battery ( Northstar) was only a few months old and still extremely healthy and capable. I turned off the Hvac fan for a ~ 24 amp load, and arrived at my destination nearly 2 hours later with battery holding 12.2volts.

I stopped for beer too, turning engine off, without any fear what so ever it would not restart.

I could easily have driven 150+ more miles on batteyr alone, at night and if daytime with no headlamps, 300 miles.

So the distance/time any vehicle can drive without a functioning charging system depends not only on the capacity of the battery, and its state of charge, but also the amount of amperage it must deliver to run the engine, and this can be wildly variable.

My reman'd alternator failed as the new sliprings were not installed properly, and one brush had been bridging both slip rings. It stopped working when the brush bottomed out on the area between the slip rings. This took about 15K miles with lots of heavy, use before the brushes wore to this point.

I Honed and then polished the slip rings, then modified the brush holder to align brushes with the slip rings and have worked the alternator hard, often, since.

I had purchased a new, Malaysian made, Autozone alternator, delivered in less than 24 hours, and installed that at time of original failure, and only got around to fixing the failed reman in my own time several months later, at which point I returned the spit and polished reman, as it has better low rpm output.

The reman had a thick layer of paint between rectifier plates and alternator body, inhibiting heat transfer to body.

There's all sorts of ways a reman can be poorly reman'd, but also, if done correctly, can be as good as new, or perhaps better.

If there is a local place which rebuilds starters and alternators, keep them in business, by giving them your business.
 
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