Car and engine noises you shouldn’t ignore

Though it’s normal for cars to make various sounds, unusual noises can act as warnings about the vehicle’s health and condition. Loose, overheating, or worn car parts often generate specific sounds, allowing you to react timely. But to do that, you must know the difference between common car and engine noises and understand their meaning.

Whether it’s a potential engine failure or a safety risk, identifying the problem early can help you avoid various dangers and additional expenses.

Understanding the difference between whistling and whining sounds

From bad window seals to a cracked turbocharger hose, whistling and whining sounds can warn about a range of issues. Since these sounds can vary, it’s crucial to understand their severity and where they’re coming from.

Whistling sounds are usually caused by air coming through a small opening, while whining often warns about mechanical issues, such as worn or dried-out moving parts.

Usually, the loudness of each noise indicates the severity of the problem. For instance, if a major whine or whistle appears out of nowhere, you should stop the car immediately to make sure it’s safe to continue driving. You can take it easy in less severe situations, but it’s always better to be safe than sorry.

Is there an easy fix?

Depending on the problem, some fixes are straightforward. Even windshield wipers or loose plastic bits around the car can cause a whistling sound, and replacing them can solve the issue.

Some drivers also have deer whistles on their cars, which whistle when going above 30 mph.

However, many unusual whistling and whining sounds are caused by damaged turbocharger hoses, an intercooler, a vacuum, or an exhaust leak. Fixing some of these problems can be as easy as reconnecting the hose, but most repairs require specific tools and knowledge.

Either way, addressing such issues is necessary to prevent further damage.

Ticking and knocking: engine warnings

Knocking and ticking sounds often relate to the engine, especially when their rate changes as you step on the gas. Anything from a gentle ticking to a metal-on-metal knocking can warn you about low oil pressure or broken rods, and most of these issues require your immediate attention.

What does it mean when your car makes a ticking sound?

If you hear a ticking sound in your engine bay, it can indicate that some moving parts are out of order or poorly lubricated. Usually, it’s less intense and not as serious as an engine knock, and immediate action can prevent damage.

Your engine can start ticking for several reasons:

• Low oil pressure is the most common reason for a ticking engine, often caused by the lack of oil or a worn oil pump. A warning light should appear in your instrument cluster.
• Noisy valvetrain. Most modern cars have self-adjusting valves, but some engines still have valves that must be aligned. Otherwise, they emit a ticking noise and can eventually damage the engine.
• Faulty spark plugs. Loose or faulty spark plugs can cause a ticking noise. Faulty spark plugs don’t ignite the fuel mixture at the right time, while incorrect installation causes leaks.
• Damaged engine accessories and belts. A belt or a pulley can be damaged, causing a ticking noise when the engine is running.
• Exhaust leak. Small exhaust leaks, especially close to the engine, can emit ticking noise. Look for black spots to find the leak.

Check your engine oil level when you notice a ticking sound – your engine can burn or leak oil, and driving without it will cause serious damage. Either way, take the car to a repair shop to find and fix the problem.

Engine knocking is more serious

Usually, an engine knock develops from ticking or appears when something snaps, warning you about serious problems.

Depending on the severity of this noise, it can be anything from low-octane fuel or carbon deposits inside the cylinders to an incorrect ignition timing or a snapped connecting rod. Running a knocking engine can lead to serious damage, so it’s recommended to turn it off immediately and contact your mechanic.

Brake and transmission problems

Many parts of the brake system and transmission move as you drive, often maintaining contact with other metal parts. They are quiet when everything’s in order, but even the smallest issues can cause distinct noises, helping you take timely and appropriate actions.

Brake squeal or grind: when your brakes cry for help

If you hear squealing, grinding, or knocking while braking, your brake pads or rotors may be worn or damaged.

Brake pads consist of a steel backplate, which is covered with a thick metallic frictional material. When this frictional material wears off, the steel backplate touches the rotor, causing unsettling squealing or grinding sounds. Brakes also become less effective, and a brake-pad warning light may appear in the instrument cluster.

Bear in mind that driving with such issues causes serious safety risks and can damage other parts of your brake system.

If you hear knocking and feel shaking while braking, your brake rotors may be damaged or worn. Usually, they bend when exposed to extreme temperature changes, such as driving through a deep puddle immediately after hard braking.

Sometimes, even brand-new brake pads or rotors can squeal. However, this should be temporary until the top layer of these parts wears off.

Whining or grinding transmission often means serious problems

A car’s transmission should be smooth – humming, grinding, or other noises aren’t normal.

A transmission consists of many shafts, bearings, gears, valves, and other metal parts. Faulty transmission parts often cause grinding, humming, and vibrations. You can also hear unusual sounds when the transmission is low on fluid because the friction between moving parts increases.

Address transmission problems as soon as possible to avoid further damage. If possible, stop the car when you hear unusual noises and contact your mechanic. Transmission repairs can cost thousands of dollars, but sometimes a fluid change can help, especially if you notice the problem early on.

Exhaust, belts, and tires

While most unusual car sounds are deceiving, exhaust, tires, and belt systems emit distinctive and easily noticeable noises when something’s wrong. Some of these sounds aren’t dangerous, but they can warn about anything from increased emissions to a potential engine failure.

Rattling and loud engine idling usually come from the exhaust system

A car’s exhaust system controls engine noise and directs exhaust fumes from the exhaust manifold to the outside of the vehicle. It consists of a few metal pipes with resonators, mufflers, and catalytic converters in between, which can get damaged and cause unpleasant noises over time.

Corrosion is one of the most common exhaust system problems because it faces extreme temperature differences and road grime. A car idles and runs louder when there’s an exhaust leak, and the bigger the hole – the louder the noise.

Rattling is also common, and it appears mainly for 2 reasons. Since rubber mounts hold the exhaust to prevent cracks and vibrations, you may hear rattling when these mounts stretch or crack. Also, the metal sheets inside the resonators and mufflers can become loose, causing annoying rattling noises.

Usually, you can check if the rattling sound comes from the exhaust by yourself. All you have to do is to grab and wiggle the exhaust from side to side, listening for any familiar noises. Don’t forget to wear gloves and don’t touch the exhaust when it’s hot.

Squealing belts: don’t let them squeak past your attention

Most cars have 1-2 serpentine belts in the engine bay, rotating the power steering pump, a generator, and other systems. Most manufacturers recommend replacing them every 60,000 miles or every 3 years, otherwise, belts often start to squeal. At first, the sound is intermittent, growing into a constant squealing later on.

The squealing is a good warning to replace your serpentine belts, otherwise, it may snap, disabling some systems and potentially overheating or seizing your engine. Replacing the serpentine belts can be pretty difficult, especially in modern cars, therefore, it’s often better to leave the job to professionals.

The importance of tire noises

All tires emit some kind of noise, especially low-profile or off-road ones. However, excessive, intermittent, and unpleasant sounds can warn about serious safety risks and cause tragic consequences.

Inspect your tires visually whenever you hear an unusual sound coming from them. The clicking sound from the wheels is often caused by small objects stuck in tire tread grooves, while bad wheel alignment or damaged tires can cause tire humming.

Remember that a worn suspension can also be the reason behind damaged tires, especially if you see uneven tire wear, such as inner, outer, or patch wear.

If you’re thinking about replacing your tires, take your car for a professional inspection first, especially if you notice uneven wear. Solving current problems will ensure that your new set of tires will last longer.

Unusual start-up sounds

Many car components endure stress upon starting the engine. Therefore, this moment can help identify issues early, ranging from loose bolts to potential fire hazards.

Despite the severity of the issue, knowing the difference between a bad and a good-sounding engine start-up can prevent serious problems.

Grinding when starting

Once you turn the car key, a powerful electric starter motor engages and connects with your engine. When a starter motor fails or wears down, you may hear unpleasant metallic grinding noises. It means that either the starter doesn’t fully engage or the gear is damaged.

Some drivers ignore this issue without understanding that a faulty starter motor can damage the flywheel. So, if the grinding is coming from a starter motor, it will probably fail soon, potentially causing even more damage and leaving you stranded in some parking lot.

Take the car for a professional inspection and get the damaged part replaced to avoid unpleasant situations.

Hissing under the hood

If your engine sounds like a snake upon starting, there are probably gasses or compressed air coming out through a tight spot somewhere. Either way, a hissing noise while starting the engine is never a good sign.

Some of the most common reasons for this sound are:

• Exhaust leak. Usually, an exhaust is hissing when there’s a loose connection or a crack in the system, creating a tight gap for exhaust gases to leak through.
• Vacuum leak. Most cars have vacuum systems that must be airtight, and a leak can start hissing. Be careful because a leaky vacuum system can weaken the brakes.
• Loose glow or spark plugs. A loose glow or spark plug can cause an intermittent hissing because it creates a combustion chamber leak.
• Damaged hoses. Vacuum, coolant, intercooler, and other hoses can emit a hissing sound when damaged. Make sure they’re in good condition and tightened properly.

You may also hear hissing while the engine is running, warning you about various potential issues. A leaky AC or cooling system can cause it, often overheating the engine as a result. Unfortunately, many of these issues don’t have an easy fix.

Popping start-up sounds

Ignition systems in modern engines ignite fuel mixture at precise moments, ensuring a smooth and constant engine operation.

However, when the mixture doesn’t burn correctly, it pops randomly, often causing popping sounds while the engine is starting or running. Faulty fuel injectors, spark plugs, carbon buildup, and other various aspects can cause this.

Fluids

Fluids can emit bubbling and gurgling noises, and the coolant is usually the one responsible for this. Coolant transfers the heat away from the engine and other hot areas by flowing through the radiator. You may hear it flowing even a few minutes after turning off the engine – this is completely normal.

The problem appears when there’s a distinctive bubbling or gurgling in your cooling system, indicating potential air pockets inside the system. This usually happens after a coolant flush or replacing some parts in the coolant system. Bleeding the system should help, but ensure the engine doesn’t overheat until then.

Suspension, undercarriage, and steering

A car’s steering and suspension systems ensure good handling, traction, and comfort. However, they’re complicated – any loose or worn bits can cause unpleasant warning noises.

Rattling undercarriage plastic covers

Nearly all modern cars have plastic sheets covering the undercarriage to prevent rock chips, corrosion, and other damage. Obviously, plastic bits can be broken and torn off from the undercarriage, especially when driving on dirt or forest roads.

Before making any assumptions, check under your car – loose and rattling plastic covers are very common.

Humming or growling noise while driving

Humming or growling while driving usually comes from tires or wheel bearings. We’ve already covered tire-related noises, but knowing how worn wheel bearings behave is also vital.

Wheel bearings start humming when they wear out because of increased friction. Since the noise becomes louder and bearings heat up as the pressure increases, the troubleshooting is simple. 

For instance, if the sound is coming from the front wheels, listen to how it changes as you turn the car – the right bearing will hum louder while turning left, and the left bearing will be louder while turning right. As with the rear wheels, you can touch them after driving – the wheel with the worn bearing should be much warmer.

Clunking and rattling suspension

A car’s suspension has dozens of different parts, and most of them have rubber bushings or ball joints at each end, which wear out over time. One of the best things about suspension problems is that various noises give them away early on: worn bushings or ball joints cause clunking noise, while old stabilizer links start rattling.

A deep clunking can also come from shock absorbers. High-quality shock absorbers can last up to 10 years, but when they wear out, you can feel that the car is bumpy and wobbly, and you may hear clunking sounds coming from worn absorber struts.

Either way, driving with damaged suspension components is dangerous, so it’s recommended to address every unusual suspension sound as soon as possible.

Groaning or squealing steering wheel

When you turn the steering wheel, the movement transferring to the wheels includes a power steering pump, a steering rack, and multiple ball joints, creating many potential squealing, whining, and groaning spots.

If your car has a hydraulic power steering system (it means that your car needs power steering fluid), you may hear a distinctive groaning or whining sound if the steering pump doesn’t get enough fluid or is faulty. You may also feel that the steering wheel is harder to turn.

You may also hear squealing when turning the steering wheel, which is usually caused by a dry ball joint. Normally, ball joints are greased to reduce friction, but water can wash it out when a protective rubber boot doesn’t seal the joint well enough.

Buzzing noise from the dashboard

Lots of wires, control units, and relays are inside the dashboard. Some electrical components often emit distinctive clicking and buzzing sounds for some time after shutting the engine off. However, while some of these sounds are normal, they shouldn’t be loud or irritating, otherwise, you may need to replace a relay, a blower motor, or an entire control unit.

Remember that electrical faults are‌ among the top causes of car fires, so take these problems seriously. To troubleshoot electrical issues correctly, you’ll probably need a professional diagnostic tool.

How to diagnose unusual noises

Whenever you hear an unusual noise, try to evaluate how serious the problem can be. Metallic and loud noises often mean that something is broken or is going to break soon, therefore, you should stop the car.

However, if you just started hearing a humble noise, figure out where it’s coming from. For instance, if the noise changes as you rev the engine, it’s probably related to it. If the sound changes with speed, you should check the tires, wheels, or drivetrain.

When it comes to transmission, unusual noises usually change while shifting.

Understanding the vehicle history and possible issues

Regardless of how well you maintain your car, various problems can appear on the surface if the previous owner hasn’t looked after it.

Knowing the car’s history is very important when buying a used vehicle to avoid unpleasant surprises. There are 2 main precautions that can help you learn about the car’s past.

The first essential is to make sure the car has a proper servicing history. All cars require regular servicing and repairs to maintain good condition, and service records are legitimate proof. Some car owners maintain their cars themselves, but even then they should have receipts for parts they’ve bought during the ownership.

Another important step is to check the car’s history. You can learn about the car’s damages, mileage records, ownership, and other essential information gathered from governmental registries, car inspection centers, police, and other trusted sources. A vehicle history report can help you evaluate the car’s condition, reveal hidden defects, negotiate the price, or avoid a lemon. For instance, if you hear a ticking noise in the engine and a history report shows that the front end was damaged recently, you should probably avoid this car.

Never ignore the unusual noises coming from your car. Many of them pose a risk to your safety and the car, so it’s advisable to avoid driving unless you’re sure the problem isn’t serious.