Possibly the wrong alternator was installed

Tiny
HCLECKLER
  • MEMBER
  • 2009 TOYOTA CAMRY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 228,000 MILES
I bought a new alternator yesterday the girl at the store asked me 4 cylinder or 6? I said 4 she says well to be sure give me the eighth number from the VIN I told her K she said well that means it's a 6 cylinder. Well, long story short I think I bought and installed a alternator for a 6 cylinder is this okay?
Do you
have the same problem?
Yes
No
Saturday, May 1st, 2021 AT 4:43 PM

3 Replies

Tiny
CARADIODOC
  • EXPERT
The engine size doesn't matter to the generator. The reason for asking all those questions is often the generators have different mounting brackets to fit certain engines. Chrysler is well-known for having real good parts interchangeability between engines, models, and years. GM is well-known to make a large number of variations, so that is when you have to be careful to get the right part. If your generator bolted to the engine the same as the old one, and the connectors and pulley are the same, it will work, with one word of warning.

You don't need to read any further if you don't want to complicate the issue, but for the benefit of others researching this topic, there is one thing that can cause trouble later. Most of the time there were two, three or four different size generators available for a specific car model. As an example, you might find a listing for a 90-amp unit, a 110-amp, and maybe a 125-amp generator, all listed for the same car. Generators with a larger output capacity are included with options packages that need more electrical power. Years ago air conditioning was an option. It included a larger generator.

The second point of value is a generator is always only going to develop exactly as much current as the electrical system needs at that instant, and no more. If you need 57 amps, it doesn't matter if your generator is capable of developing 100 amps or 150 amps; it's going to develop 57 amps. There is one time when it will develop the full amount of current it is rated for That is during a full-load output current test that is part of a professional charging system test. That test takes only two or three seconds; just long enough to get the reading, then it's over.

Also be aware a generator is physically incapable of developing more current than it is designed for. Where the problem can occur is there is always going to be some type of fuse device in the generator's output circuit. That's to protect the wire from the battery if an internal short were to develop inside the generator. It can also prevent a fire if the exposed output terminal on the back of the generator is accidentally grounded by a wrench or some other metal tool. That fuse has a current rating selected at the factory to match the generator installed there. On older cars that was a fuse link wire that was spliced into the wire it protects. It's a smaller diameter to make it the weak link in the chain. Also, the insulation is designed to not melt or burn. With a smaller factory-installed generator comes a smaller diameter fuse link wire. On newer cars that will be a regular fuse in the under-hood fuse box, and it will always be bolted in to insure a solid connection. Fuse link wires are slow-blow fuses, meaning they take some time to burn open. If you install a generator with a larger output current capacity, it is likely to exceed the current rating of the fuse link wire, but only during that full-load output test, never during normal driving. The test will be over before that wire can burn open. That's not the case on newer cars with regular fuses. Those burn open instantly when their current rating is exceeded.

Suppose you originally had an 80-amp generator. The car would likely have come with a 100-amp fuse. Now, if you install a 120-amp generator, it's still only going to develop just as much as the car needs, until that full-load output test is performed. Under this test, there are only three values that can be found. We hope we don't find 0 amps. The ideal value is very close to the generator's rating. There is a defect that will cause it to develop a maximum of exactly one-third of the maximum rating. Most of the time, when you're not having any problem or symptom, we'll find the full rated current. If that's from the 120-amp generator you installed, it's going to blow the car's 100-amp fuse, then the charging system will be dead. There's really no defect. All that's needed is to replace the fuse, then it will be back to charging normally.

All of this story is irrelevant to your Camry. The only generator offered for any of the engines was a 100-amp. You can't get one that will blow the fuse during the charging system test.
Was this
answer
helpful?
Yes
No
Saturday, May 1st, 2021 AT 7:17 PM
Tiny
HCLECKLER
  • MEMBER
The first one they gave me the hookups were farther apart than the one in my car so the girl used the part number off the one from my car to put in the computer and see which one was recommended for my car and that's the one she gave me and it fit perfectly. But thank you for taking the time to answer my question.
Was this
answer
helpful?
Yes
No
Sunday, May 2nd, 2021 AT 2:28 PM
Tiny
CARADIODOC
  • EXPERT
The connector spacing doesn't matter as long as each one matches the plug on your car. I suspect the first one also had other differences and was for a different application.

Happy to hear you solved this. Please come back to see us again.
Was this
answer
helpful?
Yes
No
Sunday, May 2nd, 2021 AT 3:11 PM

Please login or register to post a reply.

Sponsored links