What causes you to need an alternator?

08 Apr.,2024

 

I bought my car brand-new a few years ago, with only 50 miles on it when it came off the lot. It's perfectly stock - no modifications made, though some parts have been replaced for repair purposes.

Because I have a long commute, I blew past the mileage cap for the manufacturer's bumper-to-bumper warranty long before I hit the time limit. Even so, I'm now just a bit outside of what would have been the time limit on that warranty coverage anyway.

Now, with just over 74,000 miles on the car, I'm being told my alternator is making noise and may fail soon. It hasn't been giving me problems in terms of power delivery yet, but the diagnosis does explain some other minor symptoms I've noticed. This was discovered while I had it in the shop for some unrelated issues.

The real kicker though, is that this is already my second alternator. The first failed somewhere around 40,000 miles (outside of warranty due to mileage alone, at the time). That time, it did reach the point of having substantially reduced performance before I realized there was a problem and replaced it.

So now, on a car bought brand-new, I've had two alternators either fail or show indications of imminent failure within around 40,000 miles or less.

All of the vehicles I've owned before this one were bought with at least 90,000 miles on the odometer. For each of those cars, I put at least 100,000 of my own miles on them and only (if ever) had to replace their alternators once.

The first alternator on my current car obviously came straight from the manufacturer. (Again, car was bought brand-new.) The second may have been re-manfactured (I don't recall off the top of my head - will be contacting the shop that did the work when they're open again). Regardless, it seems unusual to me that both should fail so early and both around the same time.

What could be causing this?

Vehicle details:

2012 Dodge Avenger SXT
2.4 L GEMA I4 DOHC 16V Dual VVT 6-speed automatic, FWD

If your battery needs replacing, it’s an inconvenience, but when your alternator fails, you can be stuck on the side of the road waiting for a tow truck. The alternator's job is to power your vehicle after it’s been started. It recharges your battery and powers your headlights and other accessories while the vehicle is running. When the alternator fails, the vehicle gets whatever power it can from the battery until the battery is drained or damaged. Follow these warning signs to help you know when to go to the mechanic, or find a safe place to pull over, so you can get the alternator replaced.

1. Illuminated Battery Light

Your dashboard battery light is frequently a sign that you may need a new alternator. “A battery light would indicate a charging issue as the vehicle monitors the voltage,” says Travis Mock, vice president of car care for AAA Automotive Repair Centers. In some cars, the check engine light may also come on, and/or a check charging system message on the dashboard.

The battery light may also come on for other electrical or charging system problems, including:

  • Wiring issues
  • Faulty voltage regulator
  • Worn alternator or drive belt
  • Parasitic drain (when your vehicle’s electrical system continues to draw energy from the battery when the vehicle is off)

If your battery light comes on while you’re driving, you should pull over in a safe place and get the vehicle towed to the mechanic. This is because if the alternator has in fact failed, it’s only a matter of time before your vehicle stalls, which could leave you stopped dangerously in a lane of traffic.

2. Dim or Overly Bright Lights

When the alternator doesn’t produce enough power, “one of the most common symptoms is the dimming of lights or excessive light brightness,” says Mock. The dimming (and sometimes flickering or initial brightening) can occur in your headlights, dashboard light, and/or your interior dome light.

What causes you to need an alternator?

Signs Your Alternator May Need to Be Replaced