Common Engine Problems: Warning Signs, Causes & When to Get Your Car Checked

Reviewed by Eric Shepherd, ASE-Certified Technician (and Gemba’s Accidental Social Media Star!)

You’re on your way home from a fun weekend in Rocky Point, Mexico, aka Arizona’s beach, when the check engine light comes on. Add a rough idle or a new knock, tick or rattle from under the hood, and it’s easy to picture the worst-case scenario.

But engine problems don’t always equal engine failure. Warning lights, unusual noises, misfires, overheating, smoke, fluid leaks and starting problems are symptoms — and a symptom is a clue, not a diagnosis.

Before you jump to any more conclusions and start searching the internet for a reasonably priced new engine, or new car, the first step will be to figure out what is actually wrong with it.

What Are the Most Common Engine Problems?

Different engines are prone to different problems, so there isn’t a single universal list of components that fail on every vehicle. Additionally, different maintenance requirements can come into play and drivers should always pay attention to changes in how their vehicle sounds, feels or performs.

Check Engine Light: A Warning, Not a Verdict

When the check engine light illuminates, it doesn’t automatically mean your car is failing and about to explode. Rather, it means the onboard computer system has detected a fault somewhere in the system.

A diagnostic trouble code is stored when the check engine light illuminates. The code won’t tell you exactly what is wrong and how to fix the problem, but rather it can point a technician in the right direction. That is an important distinction to make because a glowing dashboard light has the ability to make a relatively small and manageable problem feel catastrophic.

Eric Shepherd, ASE-Certified Technician at Gemba Automotive, has seen that happen firsthand. “A guest reported that the check engine light was on and the vehicle had lost its power and was in ‘limp-mode,’” Shepherd said. He added that prior to getting the vehicle towed to Gemba, the guest had already planned to replace the engine and had already broken the news to his wife and told her that they were going to have to bite the bullet and repair it.

“Fortunately, it was a failed knock sensor with no engine damage,” Shepherd said. He added, “there's no better feeling than telling our guests that it's not as bad as it might seem to be. At Gemba Automotive, we pride ourselves in diagnosing the underlying cause of failure, not simply addressing a symptom.”

If a solid check engine light appears on a vehicle that otherwise seems to be running and driving normally, it generally means it needs to be diagnosed. However, if the light is flashing or accompanied by a loss of power, shaking or other severe drivability concerns, then it needs immediate action.

Engine Misfires or Rough Running

If it feels like your car forgot how to run correctly, you might be experiencing an engine misfire. An engine misfire occurs when combustion isn’t occurring normally in one or more cylinders. This could come across as a rough idle, hesitation at the light, abnormal shaking, or a check engine light.

The cause isn’t always spark plugs. Other systems and mechanical problems that can contribute to an engine misfire include ignition components, fuel delivery components, intake problems, and sensors among other things. Rather than play the guessing game and just throwing money at parts hoping to fix the issue, a trouble-code description can help narrow it down along with further diagnostic testing.

Engine Knocking, Ticking or Unusual Noises

When it comes to engine noise, it can be a large category. A knock, tick, tap and rattle may sound equally terrifying from the driver’s seat, but they can point technicians in very different directions. And some of those noises warrant genuine concern.

“Symptoms of internal engine damage usually show in a knocking noise or a check engine light,” Shepherd explained. He added that internal engine noises typically come from the mechanical components that have worn beyond repair, likely due from missed or late maintenance, like oil changes.

But hearing a noise from under the hood does not automatically mean it’s coming from inside the engine.

“A lot of the times there’s a noise that’s not a ‘knock;’ it could be from an accessory like a serpentine belt, tensioner or idler pulley,” Shepherd said. “Last week one of our guests had mentally prepared herself for an engine replacement based on her online research. Turns out it was the cooling fan that had failed and the noise she was experiencing was from the fan blades hitting the shroud. It was a much less serious repair. She was so thrilled she brought our team some homemade cupcakes.”

Cupcakes are considerably better than an engine replacement.

Self-diagnosing your vehicle based on an unfamiliar sound or a late-night internet search can easily send you in the wrong direction.

Engine Overheating

For drivers in Phoenix, overheating deserves special attention. An overheating issue can develop from a leak, low coolant, thermostat, cooling fan, water pump, radiator issue or another fault somewhere in the cooling system. Whatever the cause is, continuing to drive an overheating vehicle can turn a minor repair into a serious problem with severe engine damage. The heat alone doesn’t necessarily cause engine failure, but extreme temperatures can expose weaknesses in an already struggling cooling system. AAA notes that cooling systems work harder in hot weather and recommends maintaining coolant and inspecting cooling-system components according to manufacturer recommendations.

If you notice the temperature gauge is climbing or steam appears, the best thing you can do is safely get off the road and turn off the vehicle to prevent it from completely overheating and destroying the engine.

Engine Losing Power or Hesitating

You’re at the stoplight ready to take off and when you press the accelerator it suddenly feels like half your horses called in sick. A loss of power can indicate an engine-related problem, but it doesn’t automatically mean the engine is worn out and ready to be replaced.

For example, the fuel delivery, ignition, air intake, exhaust restrictions, sensors and controls, turbocharger or supercharger systems on applicable vehicles, and internal mechanical condition can all affect the performance of your engine.

If your vehicle has entered into “limp mode” where the power is reduced, it might feel like the engine is done, but the system is intentionally limiting the power it can produce due to the fault that triggered it. The cause needs to be diagnosed and tested rather than assuming the worst.

Smoke From the Exhaust or Engine Bay

If your car is smoking, it deserves attention, but the context matters. Smoke from the exhaust is different from smoke or steam appearing under the hood. Take note of the color, smell and when the smoke occurs, as those details can provide diagnostic clues.

Smoke under the hood after an oil change means that some oil could have spilled and is now burning off of a hot component. If you notice it and haven’t performed an oil change or any other service recently, it could indicate there is a leak somewhere that is dripping onto something hot, or it could be another issue entirely.

Engine Oil or Coolant Leaks

Leaks can always be alarming, but it doesn’t mean that the engine has failed or is failing. When diagnosing leaks it is important to consider what fluid is leaking, where it seems to come from, and how quickly is it coming out. There is a difference between a few drops escaping and a cooling system that seems to be rapidly dumping on the ground. Be sure to take note of any warning lights, fluid level changes as well as temperature changes. That said, don’t ever open a hot pressurized cooling system to investigate an overheating problem.

Hard Starting, Stalling or No-Start Problems

Turn the key or push the button and nothing happens? The engine might not even be to blame. Starting or stalling problems can arise from the battery and charging system, starter, fuel delivery, ignition system, sensors or various controls.

In Phoenix, due to the extreme heat, the battery deserves special attention. According to AAA, extreme heat can accelerate battery deterioration, and its 2026 guidance specifically identifies batteries, fluids, belts and hoses among components vulnerable to extreme heat.

How Do You Know If Your Engine Is Going Bad?

The easiest way to tell if an engine is going bad is to have it tested. If you notice abnormal noises, repeated overheating, excessive oil consumption, ongoing misfires, smoke, significant loss of power or have confirmed compression problems, you will want to have it further tested to know what’s really going on. One or two of these symptoms alone don’t necessarily mean that your vehicle needs an engine replacement.

How Mechanics Diagnose Engine Problems

Depending on the symptoms and the complaint that brought a vehicle into the shop in the first place, diagnosing the problem might include talking with the driver about when the problem occurs, visually inspecting the components, checking fluid condition and levels, scanning for diagnostic trouble codes, reviewing live data, examining misfire information and fuel trims, performing electrical tests or testing the cooling, fuel and ignition systems. If an internal issue is suspected, technicians may also use compression or leak-down testing. Not every vehicle will need every test.

According to Shepherd, one of the biggest misconceptions drivers have is that a symptom or trouble code is the diagnosis. Noises, running rough or check engine lights provide clues for technicians on where to start looking. “The real work is finding what faults create those clues,” Shepherd said, adding, “Troubleshooting the actual cause can be light and easy or heavy and hard. Every kind of failure has its unique diagnostic flow chart, and it comes down to experience and data collecting that drives the team to perform tests that reveal the faults efficiently.”

Are Engine Problems Worth Fixing?

In general, yes, engine problems are worth fixing though it depends on what has actually failed. For example, an engine problem could be traced to a bad sensor, ignition component, leak or maintenance-related issue. Other times it could involve the cooling system, timing components or cylinder head. Due to the wide range of possibilities that could be present, it’s worth it to have your engine diagnosed and tested so you can make an informed decision on how to proceed. If it comes down to a major problem, you will want to take into consideration the vehicle value, mileage, overall condition, and maintenance history.

When Should You Stop Driving?

Sometimes the smartest thing you can do for your vehicle is stop moving.

Shepherd puts safety first:

“Safety first. Anything on a vehicle that could be a safety concern is always my top priority. This includes braking systems — as we all must be able to stop — steering systems — as we all must be able to maintain a safe direction — and wheels and tires because they’re what hold you to the road. If there is anything that could lead a driver to possibly compromise their safety or another driver’s safety, please don’t drive it. Secondly, if there is anything that might leave them stranded, like an issue with the engine’s cooling system or starting or charging systems, it should be addressed. If there’s any fault that can go from an easy repair to a hard one, it’s overheating. What could have been a simple hose repair can quickly turn into an engine replacement.”

And not every warning requires a tow truck:

“If there’s a check engine light on, it’s not flashing, and the vehicle still seems to run well, drive it on in. Brakes squealing? Drive it on over. If they’re grinding, let’s get you a tow. If there’s a noise going over bumps, it’s a good time to bring it in. If you lose power steering assist and can’t safely turn the steering wheel, tow it. If the battery light has illuminated on the dash and we suspect alternator failure, we’ll arrange the tow. The theme: if it’s a matter of safety, please do not operate the vehicle and call us for a tow. If it’s not something that can leave you stranded, we’ll see you soon.”

Can Regular Maintenance Prevent Engine Problems?

Of course regular maintenance can’t ever guarantee that an engine won’t fail, but it can reduce the risk and give technicians more opportunities to catch problems earlier. Oil and filter changes, cooling system maintenance, spark plug replacements, and fluid inspections all matter and should be based on the manufacturer’s maintenance schedule.

Similarly, don’t ignore changes between services and write off the change as something “oh, I’ll have them take a look at that in two months when I bring it in for an oil change.”

You know your vehicle. If it suddenly sounds different, feels different, or runs differently, start paying attention.

When Should You Have an Engine Problem Diagnosed?

You don’t need to wait until you are broken down on the side of the road to have your vehicle brought into a repair shop. Persistent warning lights on the dashboard, running rough, power changes, or overheating and smoke can all be reasons to schedule an inspection.

At Gemba Automotive, the goal isn’t to assume the worst. It’s to determine what’s actually causing the symptom before recommending a repair. Because sometimes the terrifying engine noise really is serious. And sometimes it ends with cupcakes.

Frequently Asked Questions About Common Engine Problems

What are the most common engine problems?

Common symptoms include check engine lights, misfires, unusual noises, overheating, loss of power, smoke, fluid leaks and starting or stalling problems. Each symptom can have multiple possible causes.

How do you tell if your engine is going bad?

Persistent knocking, repeated overheating, significant oil consumption, ongoing misfires, smoke or loss of power may warrant further testing. No single symptom automatically confirms engine failure.

Are engine problems worth fixing?

Often, yes, depending on the cause. Proper diagnosis should identify what failed before you compare repair needs with the vehicle’s value, mileage and overall condition.

What causes an engine to misfire?

Possible causes include ignition, fuel-delivery, air-intake, sensor, control-system and mechanical problems.

What causes engine knocking?

Different mechanical or combustion-related conditions can produce knocking noises, but not every noise under the hood is true engine knock.

Can you drive with an overheating engine?

Continuing to drive an overheating vehicle can lead to serious engine damage. Safely stop the vehicle and seek assistance rather than trying to push it farther.

Does a check engine light mean the engine is failing?

No, not usually. A check engine light indicates the vehicle detected a fault, but diagnosis is needed to determine the underlying cause.

How are engine problems diagnosed?

Technicians use the symptoms, vehicle history, inspection, diagnostic codes, live data and appropriate electrical, mechanical or system-specific testing to narrow down the actual cause.

Get Your Engine Problem Diagnosed at Gemba Automotive

Engine noises, warning lights, overheating, misfires and loss of power can have many different causes. Proper testing can help determine whether you’re dealing with a maintenance issue, a failing component or a more serious engine problem before repairs are recommended.

Schedule Engine Diagnosis or Engine Service at Gemba Automotive.