12 Signs Your Engine Is Going Bad

Engines are complex and have many components which all are required to work flawlessly in order to have a high-performance engine. But, all engines will be worn out after some time. You can prevent and delay your car engine from going bad. Here are 12 signs that your engine is going bad:

Key Takeaway

12 Signs Your Engine Is Going Bad

  • Rod Bearing Making Knocking Noise
  • Main Bearing Noise
  • Metal Shaving in Engine Oil
  • No Engine Oil – Lack of Lubrication
  • Worn Engine and Extremely Low Power
  • Engine Misfire
  • Clicking noise
  • Sudden Loss of Power Due To a Broken Timing Belt
  • Loud Ticking Noise
  • Worn Oil Pump
  • Severe Engine Overheating
  • Fuel Leak

1. Rod Bearing Making Knocking Noise

Rod Bearing

A clear sign that your engine is going bad is when the road bearing starts to make knocking noise. The knocking noise coming from the rod bearing is accompanied by a major decrease in engine power. Normally this is caused by not changing the engine oil on time and low engine oilOpens in a new tab.

When a rod bearing is worn, it will allow the piston to rock back and forth while hitting against the cylinder walls. Eventually, the vehicle will throw a rod and cause the engine to seize. The pistons will get damaged from hitting the cylinder walls. Engine oil will slip into the combustion chamber and will burn with the air-fuel mixture.

2. Main Bearing Noise

Main Bearing

The main bearing is located between the crankshaft journal and the engine block and has a function to allow the crankshaft to rotate without friction. The crankshaft journal has holes that allow engine oil to pass through them and lubricate the crankshaft journal and main bearing. In case of not changing the oil on time or lack of engine oil, the main bearing will run dry and cause friction between the crankshaft journal and the main bearing.

A worn or bad main bearing sounds like marbles hitting each other. The noise can also be knocking, rattling, and metallic and will come from the lower end of the engine. The noise progress louder as the vehicleOpens in a new tab.

3. Metal Shaving in Engine Oil

metal shaving in oil

When the main bearing is severely worn, you will notice metal shaving, copper sheen, or chunks of metal during an oil change. If metal shaving, copper sheen, or metal chunks are found in the engine oil, that means the engine is severely worn and needs to be rebuilt.

If there is a noticeable amount of metal shaving in engine oil, that means the rod and main bearing are worn. You should always inspect the engine oil that you just drained and look for metal shavings. Sometimes large pieces of metal can be found during the inspection. I have a permanent magnet built on the bottom of my oil pan. The magnet helps collect the metal shaving circulating in the engine oil.

4. No Engine Oil – Lack of Lubrication

No Engine Oil

All moving components require some form of lubrication. Even a slight oil leak can leave your engine with insufficient oil. Sometimes drivers do not know the vehicle has lost a considerable amount of engine oil.

Bad oil pump gaskets and seals can cause severe oil leaks over time due to high temperatures. Over time, due to the high temperature, the gasket and seals will begin to deteriorate. When this happens, there will be a large puddle of oil on the ground.

An oil leak can be caused by a bad rear main seal, worn oil pan gasket, severe valve cover gasket leak, bad oil pan drain bolt, bad oil pump gasket, worn camshaft, and crankshaft seal, loose oil fill cap, worn oil cooler gasket, bad oil pressure sensor seal and cracked engine block.

5. Worn Engine and Extremely Low Power

Engines that have high mileage are usually worn out because of the normal wear and tear that comes with all those miles. A compression test can help determine the cause. Usually, a compression test can help determine worn piston rings, cylinder walls, bad intake or exhaust valves, and bad head gaskets. All cylinder compression should have a similar reading. Normally, the engine can still be saved by completely rebuilding the engine.

6. Engine Misfire

Regular engine misfires can be a sign that your engine is going bad. An engine misfire can be caused by bad spark plugsOpens in a new tab.

However, if all the above does not fix the issue then most likely the problem is mechanical. Again, a compression test should be performed.

7. Clicking Noise

All moving parts should be lubricated in order to reduce friction and heat. When the timing chain does not receive enough lubrication, it will start to make a loud clicking or tapping noise and gradually become louder when the engine speed increases.

A clicking noise is usually caused by the timing chain. A worn timing chain can cause clicking noise or a completely worn timing guide or timing chain tensioner can also contribute to the noise. If a timing chain is loose enough, the engine can skip a tooth and this can cause valve damage for an interference engine. Sometimes broken timing pieces can be found during assembly.

8. Sudden Loss of Power Due To a Broken Timing Belt

When the timing belt breaks, it can cause valve damage in interference engines. The valve hits the piston causing it to bend. The end result is low compression. However, if an engine is non-interference then there will be no valve damage, and a replacement of the timing system is required. A timing belt can break due to normal wear, a weak timing belt tensioner, a bad water pump, and a bad idler pulley.

9. Loud Ticking Noise

If your engine is making a ticking noise, it is a clear sign that some parts are worn and need replacing. If the ticking noise is coming from the right side of the engine where you have no belts, it could be a problem with the valves or even how the engine connects to the transmission. It could also be that one of the bolts on the flexplate that connects the engine to the transmission got loose and is touching the engine.

If the ticking noise is coming from the left side of the engine where you would usually have a belt, it could be a worn-out timing belt.

Sometimes a valve adjustment is needed to make the ticking noise go away. Low engine oil can also contribute to the ticking noise due to a lack of lubrication. If a valve adjustment or adding more oil does not fix the issue, then a worn camshaft lobe or lifter could be the cause.

10. Worn Oil Pump

The oil pump’s job is to make sure the engine oil circulates around the engine and lubricates all moving parts such as the hydraulic lifters, the camshaft, the crankshaft, main bearings, rod bearings, the balance shaft, and timing chain. The engine oil first gets pushed through the oil filter. Then, the filtered engine oil goes to all moving components on the top and bottom ends of the engine.

When an oil pump is worn to a point where it’s not functioning properly, an engine lightOpens in a new tab.

11. Severe Engine Overheating

A severe engine overheating can cause the head gasket to give out, therefore, causing low compression. Overheating can cause all sorts of issues such as low compression, ignition coil melting and getting stuck to the engine, and any plastic component or wire around the engine.

12. Fuel Leak and Engine Fire

Although this is rare it can occur. Usually, a leak can be caused around the fuel rail, fuel pressure regulator, fuel line, poor fuel connector, and so on. When there is a fire this will cause surface engine damage and eventually a useless engine. Fuel smell can be smelled through the vents. Whatever you do, pay attention to these warning signs.

Igor Iwanowski

I am a certified Automotive Service Excellence (ASE) mechanic since 2018. I specialize in Brake systems, dashboard warning lights, EGRs, general engine problems, EVAP and Emissions issues.

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