10 Signs of a Bad Engine & Replacement Cost

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signs of a bad engine

It was a beautiful day, and I was on my way to meet my friends for lunch. As I turned the corner, I heard a strange noise coming from my car. The engine was making a loud grinding sound, and I knew it wasn’t going to last much longer. I had no choice but to pull over and call a tow truck.

I waited for what felt like hours before the tow truck finally arrived. The driver came over to take a look at my car and shook his head in disbelief. “This engine is completely shot,” he said. “You’re going to need a new one.”

I couldn’t believe it! My car only had about 50,000 miles on it, and now it needed a new engine. Had I focused on the symptoms of engine failure, that day could have been avoided.

If you have faced a similar situation and are curious to know about common signs of engine failure, then this article is for you!

How Does An Internal Combustion Work?

Engine components work together to create the power needed to move your vehicle. The engine’s pistons move up and down, which turns the crankshaft. The crankshaft is connected to the engine’s flywheel, which helps keep the engine running smoothly.

As the engine’s pistons move up and down, they create a vacuum in the combustion chamber. This vacuum pulls in air and fuel from the engine’s intake manifold. The air and fuel are then mixed in the engine’s cylinders. The spark plugs ignite the mixture, which creates power.

The power created by the engine is used to turn the car’s wheels and move them forward or backward.

Signs Of Engine Going Bad

Many signs can indicate an engine is going bad. Some of the most common symptoms include:

  1. Check Engine Light
  2. Blue Smoke
  3. Overheating
  4. Too Much Fuel Consumption
  5. Low Engine Power
  6. Knocking Noise
  7. Rough Running Engine
  8. Oil Leaks
  9. Black Smoke
  10. Loud Engine

Let us take a closer look at these signs:

1. Check Engine Light

One of the most common signs of engine trouble is a check engine light. If your engine is having problems, the computer will detect it and turn on the check engine light.

The computer that turns on the check engine light tells you that there is a problem with your engine. It may be something minor, but it’s best to get it checked out by a mechanic.

Check engine light can indicate many different engine problems. Ignoring the check engine light can further damage your engine and may void your warranty.

If you see this light come on, do not ignore it! The sooner you get your car checked out, the better.

2. Blue Smoke

If you see blue smoke coming from your car, it may be a sign that your engine is going bad. Blue smoke is caused by oil burning in the engine. This can happen when the engine isn’t getting enough air or when the engine is overfilled with oil.

Blue smoke is not only an indicator that the engine is going bad, but it’s also an indication that the engine needs service. Ignoring this symptom can lead to more engine damage and may even result in an engine failure. If you see blue smoke coming from your car, immediately take it to a mechanic.

3. Overheating

If your engine is overheating, it’s a sign that something is wrong. Overheating can be caused by many different things, such as a coolant leak or a problem with the engine’s cooling system.

Overheating can also be caused by something as simple as a dirty air filter. If your air filter is dirty, it will prevent air from flowing into the engine. This will cause the engine to overheat and may damage the engine. Be sure to change your air filter regularly to prevent this from happening.

Ignoring an overheating engine can lead to engine damage or even engine failure. If your engine is overheating, pull over and turn off the engine immediately. Then call a tow truck to take your car to a mechanic.

4. Too Much Fuel Consumption

If your car is consuming too much fuel, it may be a sign that the engine is going bad. This can be caused by several things, such as a problem with the engine’s ignition system or a leaking fuel injector.

A car consuming too much fuel will have reduced power and performance. It will also produce more emissions. If you notice that your car is consuming too much fuel, take it to a mechanic to have it checked out.

5. Low Engine Power

If your engine is losing power, it’s a sign that something is wrong. The engine may not generate enough power to run the car, which can cause a lot of problems. You may not be able to accelerate, or you may feel like your car is “sluggish.” This can be a sign that the engine is about to fail.

If you experience low engine power, take your car to a mechanic as soon as possible. The engine may need to be replaced or repaired. Depending on the extent of the damage, repairs could be expensive.

6. Knocking Noise

If you’re hearing a knocking noise or any strange noises coming from your engine, it’s time to take your car in for service. This noise is an indication that something is wrong with the engine, and it’s only a matter of time until it completely fails.

A knocking noise is usually caused by engine wear and tear. It can also be caused by a problem with the engine’s valves or pistons. Another potential reason behind knocking is a loss of engine oil, and if left unchecked, can cause serious damage to your engine.

7. Rough Idle

One way to tell if your engine is going bad is by noticing if the car has a rough idle. A car with a rough idle will not run smoothly and may stall out. If you notice your engine sputtering or shaking, it’s a sign that something is wrong.

If your car engine is running rough, don’t panic! Several things could be causing the problem, and it’s usually something that can be fixed. One common cause is a dirty air filter. A dirty air filter can cause the engine not to get enough air, making it run rough.

If your car is running rough, take it in for a tune-up or repairs as soon as possible. Do not drive your car if it is running rough, which can damage the engine.

8. Oil Leaks

If you see oil patches under your car’s engine, it’s a sign that the engine is leaking oil. This can be caused by several problems, including a faulty seal or gasket, worn-out bearings, leaking oil pan drain plug, or a crack in the engine block.

If you notice an oil leak, take your car to a mechanic as soon as possible for engine repair. Continuing to drive with a leaking engine can damage the vehicle and lead to costly repairs down the road. In addition, oil leaks can be a safety hazard, as they can cause the car to skid or lose traction while driving.

There are a few things you can do to prevent oil leaks from happening in the first place. Make sure to have your car serviced regularly, and keep an eye on the engine for any signs of wear or damage.

If you’re handy with tools, you may be able to fix an oil leak yourself. However, it’s important to be aware of the dangers involved in repairing an engine, and it’s always best to consult a professional if you’re not sure what you’re doing.

9. Black Smoke

If your car is producing black smoke, it might be time to change or repair the engine. The black smoke that emits from car exhaust pipes results from the incomplete combustion of gasoline.

When the air and fuel mixture in the engine is not ideally balanced, the fuel will not burn completely. This leaves behind a residue of unburned fuel in the engine and exhaust system, combining with oxygen to create black smoke.

Several factors can contribute to the formation of black smoke. One is the age of the car. Newer cars have more sophisticated engine management systems that help to optimize the air-fuel mixture, making it less likely for unburned fuel to accumulate and create black smoke.

Another factor is the quality of gasoline. Cheaper, low-quality gasoline will often contain more sulfur, which can cause the fuel to ignite prematurely and create black smoke.

10. Loud Engine

It might be nearing failure if your car’s engine makes too much noise. There are various reasons why a car engine might be excessively loud, and it’s important to identify the cause as soon as possible. In some cases, the problem can be resolved with a simple fix, but the engine might need to be completely replaced in others.

I know that a loud car engine can be annoying no matter the reason. It can be especially frustrating when I am trying to listen to music or talk on the phone, and the engine noise is drowning out everything else.

Engine Replacement Cost

The cost of a car’s engine replacement can vary depending on the make and model of your car. For example, engine replacement for a Honda Accord tends to be around $4000, while engine replacement for a Ford F-150 can cost anywhere from $6000 to $8000. The price also depends on whether you choose to replace the engine yourself or have a mechanic do it for you.

If you’re facing engine problems, the best thing to do is to take your car to a mechanic and have them diagnose the issue. They will tell you what needs to be done and give you an estimate of the cost. In some cases, engine replacement might be the only option, but in others, there might be a less expensive repair that can be done.


There are a number of signs that your vehicle’s engine might be failing. If you notice any of these signs, it’s important to take your car to a mechanic as soon as possible. Continuing to drive with a failing engine can damage the vehicle and lead to costly repairs down the road. Be sure to keep an eye on your engine, and if you’re ever unsure about what to do, always consult a professional.

Frequently Asked Questions

Can you still drive a car with a bad engine?

Many people would say no, you can’t. A car with a bad engine isn’t going to go very far. However, some people would say that you can still drive a car with a bad engine, but it’s not going to be easy. It all depends on the severity of the engine problem.

If you’re thinking about driving a car with a bad engine, you need to be aware of the risks. You may find that the car is more difficult to drive, and you could end up with an accident. If you’re not comfortable driving a car with a bad engine, it’s probably best to take it to a mechanic.

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