Engine oil is necessary for the effective lubrication of engine components. As a result, the oil level in your engine must be neither too low nor too high. Overfilling the oil tank can raise crankshaft pressure, damage the spark plug, and reduce engine oil pressure.

Some of the most frequent signs of overfilling the oil tank are oil leakage, a burning oil smell, and smoke. This article will review the symptoms that can occur after overfilling the oil tank. Let’s first examine the effects of driving a car with an overfilled oil tank.

Effects of Too Much Oil in a Car

It is not advised to drive a car with an overfilled oil tank. The engine may have the following issues as a result:

1) Oil Leakage

If the oil level in the engine is too high, the engine pressure will rise. This pressure can put additional strain on gaskets and seals. This can cause the gasket to weaken or create a gap, allowing engine oil to leak.

2) Reduced Lubrication

The level of oil in the oil pan will increase if the oil tank is overfilled. As a result, a fast-moving rod called the crankshaft will aerate the engine oil. This will result in the formation of froth and bubbles in the engine oil, which may result in improper lubrication in the engine.

3) Damaged Engine Parts

When the oil level is too high, the crankshaft can splash it. This can result in engine oil entering the cylinder and damaging the spark plug. Overfilled engine oil can also cause valve pipes to collapse and engine rods to bend.

Overfill Engine Oil Symptoms

If you observe any oil leaks or poor engine performance, it is recommended that you check the engine oil level. The oil level on your dipstick should be between the “min” and “max” marks. If the oil level is slightly higher than “max” or “full,” it should not be a problem. 

However, if there is half a quart or more of extra oil, the engine oil is overfilled. Some of the symptoms that will appear if the engine oil is overfilled are –

1) Burning Oil Smell: If the oil level is too high, it can leak into hot engine components. This can cause oil to burn and emit a burning oil odor from the engine. Furthermore, you may find our “Oil Smells Like Gas” article helpful in addressing the issue.

2) Poor Engine Performance: Excessive engine oil can pass through the piston rings, enter the cylinder, and come into contact with the spark plug. If the spark plug is fouled, the engine may misfire. Overfilling the oil can also cause stalling and rough idling.

3) Engine Noise: If the oil level is too high, the crankshaft’s connecting rod will whip into the oil. This can cause a rattling sound when driving. Metal shavings in oil contact can also cause a grinding noise as the overfilled engine oil ages.

4) High Oil Pressure: If the engine oil is overfilled, the oil flow in the engine will be restricted. Engines will also face a lack of lubrication issues. This will increase the oil pressure on the oil pressure gauge.

Also Read: Low Oil Pressure Symptoms

5) Exhaust Smokes: If the engine oil level is too high, you will see blue or white smoke coming from the engine. This is due to crankcase overpressure allowing oil to pass past the piston rings and enter the cylinder. It can then be burned in the combustion chamber, producing white or blue exhaust smoke.

6) Overheating: If the level of engine oil is too high, foam and bubbles can form. This could lead to a lack of lubrication in the engine, which would increase friction and cause overheat.

7) Oil Patches: If the oil is overfilled, you may notice oil patches where the car was parked. Overfilled engine oil can leak through the PCV valve or when extra pressure is applied to the engine’s seals and gaskets.

How to Remove Overfilled Engine Oil

If you’ve driven a car with an overfilled oil tank, bubbles and froth have most likely formed.In that scenario, it is advised to flush the engine oil and replace it. However, if the oil is still in good condition, you can drain the excess oil.

Method No. 1 (Manually Removing Excess Oil)

  1. Use a jack stand to raise the car.
  2. Remove the oil pan, then the drain plug.
  3. Allow some oil to drain into a bucket.
  4. Reinstall the drain plug once you believe all of the surplus oil has been drained. For example, if there is a quart of extra oil, drain it into a bucket. It is recommended that you drain some of the excess oil first rather than all of it at once.
  5. Examine the oil level. If there is any excess oil left, repeat the process.

Method No. 2 (Using an Oil Extractor Pump)

  1. Plug the oil extractor pump into a power socket.
  2. Insert the pump tube through the oil dipstick hole.
  3. Start the oil extractor pump. Allow the oil to drain into a bucket.
  4. Stop and check the oil level periodically to know how much oil is removed.

FAQs On Overfill Engine Oil Symptoms

Overfilling engine oil might result in a lack of lubrication. The friction between the metal parts will increase, and as a result, grinding and clunking sounds might be heard. A rattling sound can also come from the engine when the crankshaft's connecting rod is aerated in overfilled engine oil.

Overfilling the oil tank by half a quart or more might put excessive pressure on the crankcase. It can result in poor lubrication, oil leaks, and a burning oil smell. Because most engines can only handle 5–6 quarts of oil, you should drain the excess 1 quart.

Engine oil spills as a result of increased crankcase pressure. Extra engine oil can mix with diesel inside the combustion chamber. Oil in gasoline engines gets burned and released as smoke from the exhaust.

But it might result in a feedback loop in diesel engines. This indicates that the engine won't shut off until all the oil and fuel have been burned. This can cause the diesel engine to malfunction.


To summarize, overfilling the engine oil is not advised. Overfilled oil can put extra strain on the crankcase. This can cause misfires, oil spills, and engine lubrication issues. Most engines only require 5-6 quarts of engine oil. Always check the owner’s manual to determine how much oil your engine requires. Make sure to drain any excess engine oil manually or by using tools.

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