New alternator?

[Christopherrr]

how can you tell when you need a new one? I looked down there and it seems fine (though a lil dirty looking)...but it does have 140K on it. Funny thing is that my battery went dead Sunday morning, but I drove her plenty and was fine all Saturday. For some reason, it just went dead. Anywho...I figured the alternator...but I replaced the battery and been driving her for the last few days and she's been fine, good charge and no drop in voltage...so I don't know. Is there a rule of thumb to follow? $108 is cheap insurance...but if I can hold on to it...I'd like to.

Thanks again fellas...

[Timbers]

Well

There are tests you can do on the alternator. The easy way is to take it off and take it to a parts store, most check it for you. The ones around where I live have a machine that can test it for you.

Usually a dead alternator will make your charge light come on. If the system doesn't detect a higher voltage with the engine running (Because the alt puts out more than 12V when spinning in order to charge the system) it will throw a light.

I would stick a volt meter on it with the engine off, should get 12V maybe a little more. Start the car, it should jump up to between 13.8 and 15V?? I think. Any more, or any less, its not working right.

I have had alternators intermittently go bad. Where they don't put out a voltage at first, but 10 minutes down the road they start charging again. I always have had a charge light when I have had alternator problems, without fail.

Feel free to blast me if I am wrong with any of this! haha

...Tim

[DeWynter]

sounds like the alt isnt the problem, but get it load tested for sure. When they go, or are going they are easy to test. Start the car turn on all the lights and the heater, step on the brake while in gear, this does several things one puts full load on the alt. and lowers the RPM of the vehicle, there by making it charge the most at the lowest RPM, It shouldnt fall below 12 volts or it may be bad or going bad.

[TraceZ]

If you are nervous, pull it apart and inspect the brushes. Lube the bearings while you are at it, and if you feel bold, clean it up on a wire wheel... It'll look like new.

You should see mine!


There is a hole in the case to insert a paperclip right behind the brushes. Use a paperclip during reassembly to hold the brushes back so you can get it all back together. Don't forget to pull out the paperclip after you are done! (it wont work very well if you forget) LOL

[Christopherrr]

Don't forget to pull out the paperclip after you are done! (it wont work very well if you forget) LOL

HAHAHAHA!!! yeah...I bet! HAHAHA!!!

[MN6WS6]

Actually, if you have an Autozone in the neighborhood, go by there. They should have a machine called an ARBST. It is a roll around machine that checks electrical systems. ARBST stands for Alternator Regulator Battery Starter Tester. It can check all that stuff without removing anything from the car.

[Z Ya Later]

A real easy way to see if your alternator is working is to simply pull the battery off while the motor already running. Not sure how much newer cars like this, but for older cars it works without a problem (to my knowledge). If I'm wrong, please let me know. But, if there are no problems, that's a quick and easy way to do it in your driveway.

[Jeff_in_Atl]

A real easy way to see if your alternator is working is to simply pull the battery off while the motor already running. Not sure how much newer cars like this, but for older cars it works without a problem (to my knowledge). If I'm wrong, please let me know. But, if there are no problems, that's a quick and easy way to do it in your driveway.

I've done this many times. Crank it, disconnect the battery, rev it to ~1500RPMs, turn on the lights, high beams, rear window defogger, AC on high. If it stays running, the alternator and regulator are fine. If it won't keep running, replace the alternator and regulator.

[TraceZ]

Here are some pics of what a OEM alternator looks like after you hit it with a wire wheel. It didnt take long, and it brightened right up. Also note the picture of the guts, including the brushes.

Have I mentioned that I miss my car recently? I really do. Winter sucks. And, I have to say, DAAAAAAAMMM that is a clean engine!