Hey guys. I got the alternator replaced under warranty on my 2003 911 C2 in October of last year.

The car wouldn't start again and the shop I was at said the battery was fine and they thought the alternator was bad.

Could the alternator be bad again after 6 months or do you guys have any other ideas on what might be going on here. The car is out of warranty now but I am going to take it back to Porsche to see if they will stand behind there warranty replacement in October. It is not a daily driver, so I know that puts more strain on the alternator, but 6 months doesn't sound right.

Any ideas would be appreciated. Thanks guys.

 

What about the voltage regulator for the alternator? Not so certain on porsches, but in general, bad voltage regulators can drain voltage from the alternator when the car is off. On some cars, the voltage regulator is built in to the alternator and some (usually older), the regulator is independent from the alternator.

Hey, the alternator was brand new and not a rebuilt right? Assuming you got one from a Porsche dealer.

 

I don't believe Porsche will replace it again under warranty. Usually you have to pay for the part to get it replaced. GL

 

Try to test your alternator by starting your car up, disconnect the negative on the battery, and turn on the a/c, stereo and lights. If your engine is still running, the alternator should still be good. If your car starts to bogg down and shut off = bad alternator.

 

I had an alternater go bad out of warranty. It was replaced with a new unit that came with a 2 yr warranty even though my car itself was out of warranty. I think you might be able to get a new one under warranty again since the one that went bad wasn't that old ...

 

Yes, it depends on the dealer and your relationship to them but most of them now won't do that.

 

Thanks for the help guys. The dealer is saying the part has a 2 year warranty. He is skeptical it is the alternator, so I might run the test someone suggested.

I will keep you all updated. Thanks again for all the help.

 

A simple multimeter voltage test will tell you if the alternator is performing its job.

It should be around 14.4v when the car is running.

 

Right, monitor the voltmeter closely. Mine hovers just below or just above 14v. major dip just after the car is started and the auto-air kicks in, but it steadies out right away. I replaced a dead alternator at about 14K. the car had low miles, but was out of warranty time. Porsche said "thanks for calling, but no thanks." I think regular driving helps the situation. good luck.

 

If the alternator was bought and installed at a dealer, Porsche parts carry a two year unlimited mileage warranty. So if the alternator is indeed bad again, it will be covered under parts warranty.

 

http://www.bcae1.com/charging.htm


Warning!
Some people tell you that you can check your alternator by disconnecting it from the battery to see if the alternator can produce enough current to keep the engine running. BAD IDEA! Disconnecting the battery will subject the voltage regulator (and computer and audio equipment...) to significant voltage spikes which may cause an otherwise good alternator to fail. Even if there were no damaging spikes, this test would not indicate whether or not the alternator was good because the engine will easily run with a weak or failing alternator.
Simple Test: If you want to see if your alternator is producing current, turn on your headlights when you're parked and the engine idling with the headlights shining on a wall (at night). Notice how bright they are. Then turn the engine off. The lights should get dimmer when you turn the engine off. If the lights get brighter when you kill the engine, the alternator was not charging sufficiently. When doing this test, the lights should be the only load (turn the stereo, a/c and other accessories off). With a heavy load, an otherwise good alternator may not be able to produce sufficient amounts of current at idle.