If your car alternator stops working, it can cause a number of problems.
From a dead battery to a problem with your engine not starting, a faulty alternator can wreak havoc. But don’t worry.
Fixing or replacing a faulty alternator is a task that you can do with the right knowledge and tools.
In this guide, I’ll explain everything you need to know to repair or replace a faulty alternator.
What is an alternator and why is it important?
Before we start fixing or replacing it, let’s first understand what an alternator does. Simply put, your car’s alternator is responsible for keeping the battery charged and providing power to the electrical systems when the engine is running.
It converts mechanical energy from the engine into electrical energy, which is then used to power the lights, air conditioning, radio, and other electronics.
Without a working alternator, your battery will eventually run out of power, causing your car to stall and fail to start.
Symptoms of a faulty alternator
Light flickering or flickering: The first thing you’ll notice is a decrease in headlight brightness. The alternator isn’t supplying enough power to your car’s electrical system, causing the lights to flicker or become weak.
Battery warning light: If the alternator is failing, your dashboard will often display a battery warning light. This indicates that the alternator is struggling to charge the battery.
Weak or dead battery: A dead battery could mean the alternator isn’t charging properly. If the battery is constantly dying or the car won’t start after a jump start, your alternator could be the culprit.
Strange noises: A failing alternator can make a grinding or grinding sound, usually caused by worn bearings or a loose belt.
Electrical failure: If your car’s electrical systems – such as the radio, air conditioning, or dashboard lights – start acting up, your alternator may be struggling to provide consistent power.
Can You Repair an Alternator, or Do You Need to Replace It?
Now, here’s the important question—can you repair the alternator, or is it better to replace it altogether?
Repairing an Alternator
If the alternator is just having a minor issue, you can attempt a repair. For example, if the issue is a bad bearing or a loose belt, it can sometimes be fixed.
However, in many cases, especially if the alternator is worn out or the internal components (like the rotor or stator) are damaged, it’s best to replace it.
Replacing an Alternator
When the alternator is beyond repair, replacing it is your best bet. This is especially true if you hear strange noises, notice burnt wiring, or if the alternator has failed completely.
How to Repair a Faulty Alternator
Step 1: Disconnect the Battery
First, make sure the car is off, and disconnect the negative terminal of the battery. This is essential for safety, as you don’t want any accidental sparks while working on electrical components.
Step 2: Remove the Alternator
Next, you’ll need to remove the alternator. This usually involves loosening the belt that connects the alternator to the engine. You may need to use a wrench or socket set to remove bolts and screws that hold the alternator in place.
Step 3: Inspect the Alternator
Once the alternator is out, check it carefully. If you’re hearing noise, check the bearings. If the alternator output is low, you may want to test it with a multimeter to confirm whether it’s providing the correct voltage.
Step 4: Replace Faulty Parts
If you find faulty parts, such as a bad bearing or a damaged diode, these can be replaced. However, it can be tricky to replace the internal parts of the alternator yourself. In many cases, buying a new alternator may be more cost-effective.
Step 5: Reassemble and Test
Once you’ve made repairs or replaced parts, put everything back together. Reconnect the alternator and belt, then reconnect the battery. Start the engine to check if the alternator is working properly and charging the battery.
How to Replace a Faulty Alternator
Step 1: Disconnect the Battery
Start by disconnecting the negative terminal of the battery. This is essential to prevent any electrical mishaps.
Step 2: Remove the Serpentine Belt
The serpentine belt is what powers the alternator. Use a wrench or socket to loosen the tensioner and remove the belt from the alternator pulley.
Step 3: Unbolt and Remove the Alternator
The alternator will be held in place with bolts or screws. Use a ratchet wrench to remove the bolts and carefully take the alternator out of the engine bay.
Step 4: Install the New Alternator
Place the new alternator where the old one was. Secure it with the bolts you removed earlier.
Step 5: Reattach the Serpentine Belt
Reinstall the serpentine belt, ensuring it’s tight and aligned properly on the alternator pulley.
Step 6: Reconnect the Battery
After making sure everything is back in place, reconnect the negative terminal of the battery.
Step 7: Test the Alternator
Start your engine and check if the new alternator is working properly. You should see a clear improvement in the battery charge and electrical system function.
Tools You’ll Need
- Socket wrench and ratchet set
- Wrenches or adjustable spanner
- Screwdrivers (flathead and Phillips)
- Serpentine belt tool (if you need to remove the belt)
- Multimeter (to test the alternator output)
- Replacement alternator (if needed)
When to Call a Professional
Sometimes, despite your best efforts, replacing or repairing an alternator can be tricky.
If you’re not comfortable working with car electrical systems or if you don’t have the tools, it might be best to call a professional mechanic.
A pro can quickly diagnose the problem and get your car back in shape.
FAQ
How do I know if my alternator is bad?
You can tell if your alternator is bad if your headlights are dim, your battery warning light comes on, or your car is having trouble starting. A grinding or whining noise can also indicate an issue with the alternator.
Can I repair my alternator myself?
Yes, you can repair an alternator yourself if it’s a minor issue, like a worn-out bearing. However, if the alternator is completely broken or if you’re unsure, it’s often better to replace it.
How much does it cost to replace an alternator?
The cost of replacing an alternator varies depending on the make and model of your car. On average, parts and labor can cost anywhere from $400 to $1,000.
Can a faulty alternator cause a car to stall?
Yes, a faulty alternator can cause your car to stall. Since it provides power to the electrical system and charges the battery, a malfunction can lead to a dead battery, causing the engine to stop running.
Is it safe to drive with a bad alternator?
It’s not recommended to drive with a bad alternator. If it’s not charging the battery, you might get stranded once the battery loses power. The electrical systems could also stop working, leading to more serious problems.