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How to tell if your car alternator is bad

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Are you having trouble starting your vehicle?

Your car alternator going bad could be the cause behind this problem.

Here are some bad alternator symptoms:

  • Battery light comes on
  • Grinding, growling and whirring noises
  • Electronics not working correctly
  • Dead or slow car battery
  • Burning electrical or rubber smell

More in-depth explanations of each indicator can be found below.

Battery light turns on: One of the first signs that you would see if your car alternator is going bad would be when the battery light comes on. It can be mistaken for a regular battery issue, but really it’s indicating that the battery isn’t being charged. Alternators are designed to take the load from the electrical system and charge the battery. Generally, you see 13 to 15 volts with an alternator. The battery light may turn on if it goes below that, or if it starts reaching 16 or 17 volts, which indicates an overcharging problem. Overcharging can cause many other problems in your vehicle. Depending on the electrical load – that can be anything from the air conditioning running, headlights, wiper blades, the radio, even the electrical doors like those found on minivans – can make the battery warning light flicker. That’s because the alternator is fluctuating and trying to compensate for the vehicle’s electrical load. If you start seeing that, it’s a good time to bring your car in for us to check the electrical system and, specifically, the alternator. That way you don’t end up on the side of the road.

Noises from under the hood: Hearing noises that are coming from underneath the hood is another common symptom to watch out for. Due to age and wear, the bearings on alternators can start to go bad. You may notice a grinding or growling noise. You can confirm that this is the problem if the alternator is on top by placing a screwdriver on the metal part of it and holding the screwdriver near your ear. If you hear the growling sound coming from there rather than another area, then that will tell you that the bearings are the culprit. Other noises can occur if the pulleys aren’t aligned correctly or the belt pulley bearings are worn, which can create grinding or growling noises and may sound as if it’s the alternator. Whirring is another bad alternator sound that will increase in frequency when you accelerate and decrease as you let off the gas. That is a sign that the alternator is trying to work really hard and is starting to go bad.

Electronics stop working or have delayed response: If your car alternator is going bad, the electronics on a vehicle may act haywire or work slower than normal. On some cars, you can see the dashboard behaving strangely  – the gauges may be moving back and forth, the lights might turn on and off. Newer vehicles have so many electronics. The alternator’s main job is making sure the car is safe to drive on the road. So, it could begin turning off electronics to ensure the engine and brakes continue to function. Really dim or bright headlights are another sign of a bad alternator. The headlights can appear dim if the component is undercharging or overcharging, the lights may get brighter as you hit the gas.

Dead battery or battery is slow to crank: Do you have a dead car battery, or has it taken longer to crank? You might not need a new battery. The problem could lie with the alternator. As you’re driving, the alternator is responsible for charging the battery. If it isn’t able to do that well, but it has enough juice to keep the electronics running the battery won’t be charged correctly and the next time you go to start the car you’re going to either have a slow crank or no crank. It may just “click” – as if you accidentally left your headlights on. You can jump start your car so you can head over to a car repair shop. But if you experience this problem, you should bring the vehicle in so a mechanic can check it out.

Burning smell: In extreme cases, drivers may notice something that smells like rubber or electrical wires are burning. The electronics inside the alternator or the bearings become hot and, next thing you know, you’re starting to cook the insulation on the wiring in the alternator. If it’s an electrical short, that’s where you get the wire burning smell. Basically, it’s an electrical fire. When the alternator is being overworked, it tries to push too much electricity through there and will melt items. If you notice this issue, you should stop and maybe even disconnect your car battery, because if there is an electrical short you don’t want any electricity running through there.

Drivers who experience any of these bad alternator signs should bring their vehicle to a nearby repair shop. The technicians at HomeTowne Auto Repair & Tire are able to check alternators, perform courtesy inspections, and conduct diagnostic testing. 

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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The role car computers play

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

When you turn on your car, you’ll notice lots of lights on the dash and it may take a few moments before it stops looking like a Christmas tree.

The reason? There are many computers and modules that run various systems, such as the transmission and engine. Giving the car a minute allows these computers – called Electronic Control Units (ECUs) – to reset. Together, the ECUs form the Controller Area Network (CAN).

Sensors and modules send information to the computers and there are gateway modules that help direct traffic. So not only do you have sensors, you’ve got modules that actually control things, gateway modules that allow access, the CAN network, and the computer.  

Signs of computer problems and how we address them

If there’s a problem with a computer, the vehicle won’t work the way it should. You may notice a few issues. In addition to triggering the check engine light, a malfunctioning computer can impact the fuel economy and result in a no start.

Depending on what it is, there are driver information centers. It can be done through the dashboard lights or small computer screens that explain what’s going on or the system being affected.

Electronic problems can be difficult and time consuming to fix. Our technicians begin addressing the problem by performing a visual inspection. Then, we hook up the computer. We have special scan tools and we even have different ones depending on the type of car we’re working on. The scan tools at the auto parts stores may give you a code, but they don’t allow you to have full access. 

Reasons car computers fail

There are many possible culprits that can lead car computers to fail. It can be as simple as a sensor going bad and needing to be replaced.

Wiring can also become chafed. We’ve seen everything from too much being crammed under the seats, where a lot of modules are now located. In low end and high end vehicles, we have seen problems that have been the result of people spilling drinks or leaving the windows open. 

Sometimes, water leaks can occur due to windshield seals. The water goes in and it will corrode the connectors. You may not see it, so it could be difficult to diagnose because the water goes in, gets in the connector and starts to corrode it, causing an intermittent problem.

car computers
Water collected in the well of a Mercedes, causing a module to corrode.

In the case of one Mercedes, water soaked into the carpet and collected in the well, which was below the floor mat level. Overtime, this issue caused the module to corrode.

We’re finding water intrusion problems with all of the electronics in these cars – not just with the Mercedes. Even with the way the metals are sometimes made, you’re getting corrosion or connection problems, and that’s what’s leading components to fail. 

Some modules are underneath the vehicle or behind bumpers on panels. Even though they aren’t out in the elements, they see a lot of water and salt from the road. We’ve seen modules corrode on the outside and ruin the modules.

Shortage of car parts

With the parts shortages right now, where we used to be able to get just about any part within 2 to 4 days – even if it wasn’t as common – we’re starting to receive them in 2 to 4 weeks. 

For some of these older vehicles, we’re needing to rely on remanufacturers. You’re not able to get some new old stock from the dealer anymore. There’s even a shortage of used parts for some remanufacturers to rebuild them. So we may have to remove the part, send it off for repairs, and wait for them to send it back. That can take 3 to 6 weeks. 

With all that’s going on with the economy, it can delay vehicles getting fixed because we don’t have any other choice.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Did your check engine light turn on? Here’s what you need to know.

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

The check engine light turning is one problem that can be worrisome for drivers. 

When this indicator refuses to go off when someone is starting their car, or when it appears as they’re heading down the highway, it tends to come with the “Uh-oh,” reaction.

So, what should you do when a check engine light turns on?

If the symbol is flashing, you need to have it looked at right away. 

A flashing check engine light means that there’s a problem with the engine. Choosing to wait it out could damage the catalytic converter.

If the indicator is solid, it doesn’t need immediate attention. However, it’s important to have a mechanic check it out as soon as possible.

Can you drive with a check engine light on?

You shouldn’t drive if the light is flashing.

It’s OK to keep driving if it is solid, but it’s a good idea to have it checked out that same day. 

We recommend this because if it’s dangerous you’ll want to have it fixed immediately. Secondly, if you put it off too long you can get several more codes that could be related to the first one. You will likely spend more money on diagnostic testing so the auto repair shop can sort it all out.

What can cause a check engine light to come on?

There are many reasons why the light turns on, some are simple while others are more complex.

It could be anything from low oil to issues with a component, such as the catalytic converter or the coolant system.

Others causes include problems with the ignition system, fuel injection system, evaporative system – which has to do with your gas tank and gas cap – and sensors that are on various parts of the engine.

There are many reasons why the check engine light turns on.

What do we do during check engine light diagnostic testing?

Check engine light diagnostic testing starts with performing a basic check, which helps us rule out any simple problems.

Our technicians then do a preliminary code scan, which gives us a starting point, and start testing related parts.

We follow the testing procedures the manufacturers recommend and look for any Technical Service Bulletins (TSBs) and updates.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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My car won’t start. What’s wrong?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

It is very inconvenient when your car won’t start, especially if you have somewhere to be.

There are many possible culprits behind this issue.

The problem could be as simple as a car battery, alternator or starter going bad. It could also be a more complex issue.

Dead Battery 

If you hear a clicking sound or the check engine light turns on, the battery might need replacing.

Batteries can go bad for a number of reasons. Leaving your lights on is one that many of us are familiar with. 

There could also be a problem with the charging system or corrosion on the battery terminals. Electronics in your vehicle, such as clocks and computers, can eventually cause your battery to die.

Old and weak car batteries are more likely to go bad when it’s extremely hot or cold outside.

Starter going bad

A vehicle may not turn over if it has a bad starter, which is responsible for starting the engine.

It has a gear that shoots out and quickly spins, starting the flywheel.

A clicking sound can be a sign that you need a new starter. However, a car with a bad starter won’t easily start even when a jumper box or jumper cables are used. Here are some other signs that your starter is going bad.

A starter will, at times, stop working without warning.

If you turn you over a few times, you may be able to hit it right and get your car started. 

However, if this tactic doesn’t work you probably need to have it towed to a repair shop.

Alternator problem

The alternator is responsible for generating electricity, which is used for electronics or to recharge the battery.

An alternator going bad is another reason why a car won’t start.

This can be indicated by the battery light turning on or flickering. The alternator may be struggling to charge the battery, which can make it difficult to start a vehicle.

In addition to the alternator going bad, the problem may have to do with brushes or diodes. A serpentine belt could also have gotten caught around the alternator.

Other issues

Issues with a vehicle refusing to start could be more complicated and lie with a sensor or control system not functioning.

The transmission sensor, for example, could be the reason.

There may also be a problem with the fuel system, such as a bad fuel pump or the fuel filter becoming clogged.

Whatever the reason behind your car not starting, you should bring it to a mechanic or auto repair shop as soon as possible. 

Even if you’re able to get it started again, you might not be as lucky next time.

Also, the sooner you can bring it to a repair shop, the sooner they can pinpoint the issue and have you back on the road again.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics. 

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What causes a check engine light to turn on?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

A car’s check engine light isn’t an indicator that should be ignored.

The symbol clues you in that there’s a problem. The issue itself can span a number of components.

If your car’s check engine light is blinking, which means that there’s an engine issue, we recommend bringing it to a mechanic as soon as you can.

Waiting to have it checked out can cause catalytic converter damage.

A light that remains solid should be looked at soon.

Some causes include a dead car battery and spark plugs or ignition coils going bad.

The check engine light could indicate that the catalytic converter isn’t working right. This was the case with a Dodge Caravan we worked on last year.

Problems with the circuit, catalyst system and coolant system are also reasons why it turns on.

A misfiring engine is a more serious problem that the light would point out.

Before dropping your car off at an auto repair shop, make sure the gas cap isn’t loose. Loose fuel caps can trigger it, as well.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics. 

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What is an intercooler?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Parts of a vehicle heat up as it’s driven.

Certain components help cool them off.

Charles, one of our technicians, replaced the intercooler of a 2015 Audi A4 last month.

intercooler
Audi A4

Intercoolers are heat exchanging devices that are found on top or in front of the engine of supercharged or turbocharged cars. 

The turbo takes pressure from the exhaust. It spools up and sends more air into the air intake, creating more power — also known as “boost”. More power equals more heat.

A heat exchanger is needed to lower the intake air temperatures, which can prevent damage to the engine.

Air to water intercoolers are used on drag racing cars. Those using them will add ice to the intercooler, so the intake air temperature becomes even cooler.

The Audi was brought in when the check engine turned on. It had a running rich code. 

Charles disconnected the intake tube from the throttle body. He performed a smoke test and smoke started pouring out of the intercooler.

Some type of impact caused the air leak. When the air was passing through, it sucked in unmetered air, causing it to run rich.

intercooler
New intercooler and old intercooler

When you notice a problem with your vehicle, it’s important to share as much information as you can with the mechanic or auto shop.

These details — even the ones that seem irrelevant — can help them address the issue and get you back on the road sooner.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Why is diagnostic testing important?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

A customer came into HomeTowne Auto Repair & Tire with a check engine light on.

They stated that there were no problems with driving the car, but the light had turned on a couple days earlier. 

This is one problem that can be addressed through diagnostic testing.

Diagnostic testing goes beyond reading a code or looking over a vehicle.

Anybody can take a car to have a code read, or check it out themselves with a flashlight. Diagnostic testing enables technicians to dig deeper into the problem.

Codes are like zip codes — they tell us where in the neighborhood you’re supposed to be. However, further investigation is necessary, because they can mask other issues.

For example, there could be a code for a catalytic converter and we could say, “OK. We read the code. Replace it.” But the code could really be caused by oxygen sensors that aren’t reading correctly.

Through diagnostic testing, technicians are able to determine the actual reason for a failure or problem, which can help you save money in the long run.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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What is a fuel injector?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

This week, a 2008 Jeep Wrangler was brought to HomeTowne Auto Repair & Tire.

The check engine light was on, and it had a fuel injector code.

Fuel injectors send fuel into the cylinder, allowing your vehicle’s engine to run. 

To reach them, we needed to remove the intake manifold. On this Jeep Wrangler, the exhaust gas recirculation (EGR) tube runs from the valve on top of the intake.

Fuel injector
Intake Manifold

While working on the vehicle, we realized that a fuel injector was out of speculation. We will need to install new injectors and recheck it.

The check engine light turning on isn’t the only sign that the fuel injectors aren’t working correctly. You may also notice the vehicle is riding rough and lacking power.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics. 

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Is your check engine light on?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

A catalytic converter helps reduce pollution by changing a vehicle’s exhaust emission.

Ray from HomeTowne Auto Repair & Tire installed a new one on a Dodge Caravan on Monday.

The vehicle was brought to the shop when the check engine light came on. 

When checking the O2 sensors on the computer, he realized that the catalytic converter wasn’t working properly.

Catalyic Converter
An old catalytic converter and a new catalytic converter

Different types of two-way and three-way converters are available. Years ago, one-way converters were used. 

Ray installed a two-way converter, which contains chemicals that changes the air.

The type of converter a vehicle needs depends on the make and model, and how the engine runs. 

Some converters don’t go bad. 

Others may need replacing if a misfire occurs. A misfire shoots raw fuel in the converter, which can’t switch over raw fuel. 

In addition to the check engine light coming on, the smell of raw fumes is another sign that a vehicle needs a new one. However, the check engine light would be your first indicator.

There are many reasons why the check engine light turns on. If it does, it’s a good idea to bring the vehicle into an auto repair shop soon.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Is your battery light on?

In Automotive Diagnostics, News by HomeTowne Auto Repair & Tire

If your battery light comes on or flickers on your dashboard, it could be a sign of an alternator going bad.

The alternator is driven by the engine to produce electricity to run the accessories in a vehicle and recharge the battery.

Some common problems that could lead to an alternator not working correctly can be normal wear and tear, and the brushes or diodes going bad. A common overlooked problem is a drive belt — or serpentine belt — becoming loose or stretched and slipping around the alternator.

The large number of electronics in today’s vehicles and all the accessories drivers like to plug in puts a heavy load on the alternator. The alternators actually have to be more heavy duty than before so they can charge the battery at a consistent rate. 

The battery light coming on steady or flickering, especially when you come to a stop, are some signs that you’re having an alternator problem.

If you’re having a problem starting your car, it could be because the alternator is struggling to charge the battery.

If you believe you’re having any problems, you’ll want to have your vehicle checked with good electrical diagnostic equipment at your local auto repair shop. Because of the demand on the electrical system and the way alternators are designed, the old way of checking alternators isn’t always accurate.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.