Infiniti I35 Alternator Problems

I have a 2001 Infiniti I35. In the last 6 months I have replaced the alternator 3 times. The first two times were fairly easily explained (age of alternator, then replaced with a bad one), but this third has been running fine for months and then just died. Is this a problem with this car? Or is it just a coincidence? My mechanic hasn’t offered anything helpful, and I’m wondering if it’s time to replace the car.

What kind of condition is the car in, overall?
Has it been maintained at least as well as Nissan specifies?
Have you changed the transmission fluid at least 4 times so far?
Is the body free of rust?

If you can answer in the affirmative to all of the above, it would seem mighty silly to get rid of the car just because of recurring alternator failures. Perhaps it might make more sense to get a new mechanic, or at least to demand that the new alternator be a really new one–from Nissan–rather than a rebuilt one. The instance of poor-quality rebuilt alternators is…very high.

Edited to add:
On the other hand, if you are just tired of this car, and need an excuse to treat yourself to a new one, then I could certainly agree with your decision to get rid of it. I tend to keep my cars for 7-10 years, but once I get bored with a vehicle, I replace it. If you can afford to replace this car with something newer…Why not?

I’ll echo @VDCdriver here. If you are using the same mechanic…they are probably more faulty than the alternators.


Are you using Infiniti alternators?

Or store brand?

How old is that battery?

No alternator can perform properly if the battery is toast . . .

Above good comments. My 2 cents … first, consider to purchase the next alternator from Infinity rather than an auto parts store. There’s a lot of questionable quality non-oem auto parts being imported these days and sold for 1/3 price compared to the OEM version, but in some cases it is 1/3 price for a reason. Not a good reason. Second, if you have your car jump started occassionally, or you use your car to jump start other cars, this can damage the alternator diodes.

BTW, if the current alternator is an oem part, and you want to keep it, you might be able to have it fixed by your local auto-electrics shop. Often it is just a diode that needs to be replaced. Or even just a connector. If it is oem, that’s probably what I’d do rather than buying a new one, for the simple reason that the new one you buy might be worse quality than the one you have.

Third, once you get the alternator working again, might be a good time to take in in and have a comprehensive test on the battery and charging system. A faulty battery can be hard on the alternator.

There could be a wiring or battery problem causing the alternator to work harder then it should be normally. A good shop should be able to determine if that is the case or not. If the battery is fairly old it is best to replace the battery along with the alternator since they work together. The main concern is the alternator charging current should be fairly low when the battery is fully charged and the accessories are turned off. If there is a wiring problem to the regulator sense wire it could make the regulator think the battery isn’t charged and overwork the alternator.

Three times in 6 months is either a bad diagnosis or they’re being killed by an existing problem with the car and that is not being taken into consideration when or if “why” is factored in.

How certain is the mechanic that the alternators are really going bad?