2007 Chevy Aveo - battery, alternator, or something else?

Question

I bought this car when it had 120,000 miles on it, a few weeks ago, for a grand from my friend who sold it to me with the caution that it had a few issues. I am a novice driver and needed a car to get comfortable driving in. Not a brand new car that I might smash into the divider! The car had the check engine light on, but my friend said his mechanic had told him he could not identify any issues with it. Moving on ...

1. I had let it sit in the lot for almost 15 days without driving it anywhere. This was 1 months ago. But the car started and drove fine when I drove it around the city, highways included, and no problems (now that I think about it, I did find the car difficult to accelerate while on the highway. But I am a novice driver and did not think much of it then).

2. On that day after coming back home, I had left the headlights on when the car was shut down for about 20 min. That caused the battery to drain apparently. When I tried to start it the car made rapid clicking noises without the engine cranking. The battery light stayed on. I had it jumped and that fixed the problem and the battery light went off. I let it run while parked for 20 mins and had no issues when i took it around. But I never drove it longer than 20 mins or faster than 50 mph.

3. Yesterday I was driving on a highway with my mobile phone charging from the lighter port and the A/C at full blast. When I got on to the highway, the car would not accelerate smoothly, and did not get much above 60 mph no matter how hard I tried. A few min later all the lights on the dashboard went on, including the battery light. I turned the A/C off and unplugged my mobile phone which felt really hot to touch. The car radio started to turn on and off randomly all on its own, and kept doing that even when I tried to turn it off. I managed to drive off the highway, and drove for another 10 min to get home safely, parked and turned off the car. Then It would not start again, once again making rapid clicking noises when I tried.

4. I had it jumped again, and it started. This time though, the battery light continued to stay on. The car remained on for a few min. Then i tried to reach the driver side mirror and accidentally turned on the turn signal and that shut the car off right away. Now it makes those clicks again when I start.

That was the whole chain of events.

What do you guys think? Is it the battery? Or alternator? If I jump start again, and it stays on, will I be able to drive it to a mechanic that is 5 min away, traffic included? I don't want to have it towed unless I really have to.

Answer 1

Check to see where the issue lies by doing the following:

• Using a multimeter, check the voltage at the batter without the engine running. If the battery is in good shape, it should be around 12.9-13.1 volts DC (vdc). I would assume since you are getting a clicking noise, your voltage reading is going to be much lower. If you do get the correct voltage reading, you have a connection issue. This could be at the battery, or at any of the connection ends. If it doesn't have the correct voltage (reading something like 10-10.5vdc or less), you can try charging the battery. If you put the battery on a charger and it still does not respond (will not completely charge), the battery is obviously at fault.

• Jump the car and get it running. Again using a multimeter, check the voltage at the battery. Nominal voltage should be ~13.1-13.9vdc (or there about). If it is showing a voltage reading and that reading continues to drop (ie: starts at 12.5vdc, while slowly and continuously drops), the problem is probably your alternator.

If the problem is the battery (as described in the second half of the first bullet), your car will probably die on it's way to the mechanic. If the problem is your connections (as described in the first part of the first bullet), you need to figure out where the loose connection is at and get it fixed ... it will probably die on the way to the mechanic as well. If the problem is the alternator (as described in the second bullet), you can fully charge the battery, your car should make it just fine to the mechanic to have it replaced. My gut check here is that the problem lies in the battery, where it is just dieing and taking the field charge with it, not allowing the alternator to put out the required amount of current to keep the car running.

As an aside, if you don't have an multimeter, you can pick one up from Harbor Freight or the like for a cheap amount (under $5). You just need one which will give you basic vdc, vac, and ohm readings.

Answer 2

It turned out to be both the alternator and the battery. The mechanic I went to replaced them both and so far the car has been OK.

I did not have a multimeter handy and the car would not shift out of park or stay jump started, so I had to have it towed to a nearby auto repair shop to have this done.

Thanks Paulster2.