Cash for Clunkers

Tara Hornor
Written byTara HornorUpdated - January 16, 2024
Tara Hornor
Tara Hornor

Tara Hornor is an experienced writer and entrepreneur with over two decades of experien... | See full bio

John Rush
Edited and Fact-Checked byJohn RushEditor
John Rush
John Rush
Automotive Content Accuracy Auditor|||

With over four decades of experience, John Rush is a highly accomplished business owner... | See full bio

How to diagnose and fix alternator issues

An alternator is one of the main components of your vehicle’s electrical and charging system. Apart from a few hybrids, all cars with an internal combustion engine come with an alternator that is in charge of supplying power to the battery.  With wear and tear, and over time, you might have to replace the alternator, even though it typically lasts for 10 to 15 years in most vehicles. This repair of a failing alternator can be the one of many to come – read on to better understand your options and if it’s worth fixing your junk car. The costs upcoming may be more than the value of your junk car or not worth the time and it could be time to sell. However, if you want to take a shot at repairing it yourself check out this informative video below:

Reasons why an alternator might fail:

Battery going dead

If the battery is dying, it puts extra stress on the alternator as it has to work overtime, which means it wears out faster. Since the work of an alternator is to charge the battery while the car is running and ensure that electrical systems like lights, radio, etc. also work properly, the alternator over exerts itself to keep a dying battery alive.

Failed plates

There are three rotating plates spanning across a winding of copper wires, which is how the alternator generates power. If these plates fail one at a time, the alternator weakens but manages to generate sufficient power output. When the plates fail, the power will drop power levels. This wear and tear ultimately causes the battery to fail and the ignition system to die.

Worn out ball bearings

A rotor spins on a set of ball bearings on the interior of the alternator.  When the bearings experience wear over time, they tend to snag because of developing flat spots, it causes an unruly clamor, which inevitably becomes a prolonged grinding sound. In fact, the noise can get so loud that it can drown out engine sounds and even your radio.

Loose or disconnected ground wire

The alternator serves as the mounting point for the negative ground wire. The wire is generally mounted to the vehicle’s frame with a big wire that can eventually come loose. If the alternator’s base becomes unstable, it can lead to surges and severe damages to the alternator and the parts it houses within.

Damaged drive belt

If there is a worn or damaged drive belt it can cause slipping to happen on the alternator’s pulley wheel. When this happens, it can cause the alternator to put out less voltage. In the absence of a properly fitted belt, it can lead to the alternator undercharging the vehicle system, which in turn damages the alternator and kills the battery too.

Failing Alternator signs

How can you tell if the alternator is failing?

Now that you know the reasons why an alternator might fail, you can self-diagnose this problem when it happens:

Lights that are barely on

As mentioned, the sole objective of an alternator is to provide power to the ignition, starter, and other electronic systems in the vehicle. Have you notice dim lights in the interiors as well as outdoors, such as dimmed headlights or dim dashboard lights? These are generally indications of possible failing alternator.

Weak battery

A car battery won’t last forever. Even if the alternator that is charging the car’s battery is top quality and giving stellar performance, it has its limitations, and eventually the battery won’t accept charging. To understand this problem better and find out if it is the battery that has failed or if the alternator isn’t functioning anymore, all you have to do is charge the battery and restart the car. If the vehicle isn’t starting properly even after receiving a full charge, then you might have to replace the alternator.

Warning light on dashboard

Modern vehicles these days have dashboard warning lights that clearly indicate when the alternator is in need of a replacement. Check the owner’s manual for more information and if you have a failing alternator.

Odd sounds and strange smells

Hear a grinding sound? Or is it more of a whining noise? It happens because one of the several internal components of your alternative is failing and has become worn out or has completely broken down. In case you get weird odors, it indicates a damaged drive belt. If the belt can’t move around freely, the friction causes the belt to overheat, which gives out the pungent smell of burnt rubber. It causes poor alternator output. You can try tightening the belt, and if the alternator output is unchanged or the smell doesn’t go away, it means the alternator is failing.

A worn belt

This is one of the easiest symptoms to detect. All you have to do is take a peek under the hood and check your belts to see if they are properly connected to the alternator. This is done to ensure the connections aren’t too loose, overly tight, cracked or worn.

Can you make the failing alternator last longer?

At times, an alternator might fail before it is supposed to, if the protective cover from the engine gets damaged or is missing. In case water seeps into the alternator, it can cause faster wear over time. When the engine undershield gets damaged, you have to replace it right away to ensure the engine compartment is dry. Moreover, coolant or oil can leak and damage the alternator too. Please keep the alternator and engine compartment dry to prevent liquid damage to electrical components.

Cost to Replace an Alternator

What is the cost to replace an failing alternator? 

Keep in mind that replacing a failing alternator is expensive and sets you back anywhere between $400 and $850. If you buy original parts directly from a dealer, it is costlier. You can try rebuilding the unit as it hurts your pocket significantly less. The mechanic removes the alternator and sends it to a rebuilding shop, so you have to pay removal and installation charges up to $120, rebuilder’s charge that can go up to $150 and additional labor prices at times. Don’t want to go through the hassle of checking the failing alternator? Is it worth the cost to repair your junk car or should you replace it? If your car has been put through the wringer over the years and there are multiple issues with it, this might be a good time to think about to consider selling your junk car and getting a new car. It spares the trouble of checking and fixing damaged parts and you can use the amount for the old car to make a tidy down payment on a brand new set of wheels!





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