What is the car engine oil capacity?

This blog post will answer the question, ‘What is the car engine oil capacity?’, and cover topics like why we need oil in a car engine, the properties, and how oils are classified.

What is the car engine oil capacity?

Typical car engines can hold about 4-8 liters of oil on average, although the exact amount depends on the type of engine and the number of cylinders inside it:

  • About 4.5-5 liters of oil is optimum for 4-cylinder engines
  • About 5.5-6 liters of oil is optimum for 6-cylinder engines
  • About 5-7.5 liters of oil is optimum for 8-cylinder engines

Why do we need oil in a car engine?

Oil in a car engine is mainly required for lubrication or combustion, however, there are other contributions that oil makes in a car engine:

  • To reduce friction between the parts having relative motion
  • To reduce wear of the moving part
  • To cool the surfaces by carrying away the heat generated due to friction
  • To seal a space adjoining the surfaces
  • To absorb shocks and vibrations between bearings and other parts
  • To consequently reduce noise
  • To remove dirt and grit that might have crept between the rubbing parts

Properties of oil

These are the following properties of oil that are necessary to help a car engine perform optimally.

Viscosity

It is the ability of the oil to resist internal deformation due to mechanical stresses and hence it is a measure of the ability of the oil film to carry a load.

More viscous oil is able to carry a greater load, but it offers greater friction to the sliding movement of one bearing surface to another. 

Viscosity also varies with temperature and hence if a surface to be lubricated is at a high temperature, it should be supplied with oil of higher viscosity.

Flash point

It is defined as the lowest temperature at which the lubricating oil will flash when a small flame is passed across its surface. The flash point of the oil should be sufficiently high so as to avoid flashing of oil vapors at the temperatures occurring in common use. High flash point oils are required in air compressors.

Fire point

It is defined as the lowest temperature at which the oil burns continuously. The fire point must also be high in lubricating oil, so that oil does not burn in service.

Cloud point

When subject to low temperature, the oil changes from a liquid state to a plastic or solid-state. In some cases, the oil starts solidifying which makes it appear cloudy. The temperature at which this takes place is referred to as the cloud point.

Pour point

The pour point is defined as the lowest temperature at which the oil starts pouring. It is an indication of its ability to move at low temperatures. 

This property must be considered because of its effect on starting an engine in cold weather and on the free circulation of oil through exterior feed pipes when pressure is not applied.

Oiliness

This is the property that enables oil to spread over and adhere to the surface of the bearings, in order to form a protective film coating over the components.

Corrosion

The oil must not corrode the working parts and it must retain its properties even in the presence of foreign matter and additives.

Emulsification

An oil, when mixed with water is emulsified and loses its lubricating property. The emulsification number is an index of the tendency of an oil to emulsify with water.

Physical stability

Lubricating oil must be stable physically at the lowest and the highest temperatures between which the oil is to be used

Chemical stability

Oils must also have chemical stability and must not have the tendency to promote oxide formation.

Neutralization number

An oil may contain certain impurities that are not removed during its refining. The neutralization number test is a simple procedure to determine the acidity or the alkalinity of an oil. 

It is the weight in milligrams of potassium hydroxide required to neutralize the acid content of one gram of oil.

Adhesiveness

Adhesiveness is defined as the property of oil due to which all the oil particles gain the ability to stick to the metal surfaces.

Film strength

It is the property of lubricating oil due to which the oil retains a thin film between the two surfaces even at high speeds and loads. The film does not break and the two surfaces do not come in direct contact.

Specific gravity

Specific gravity is defined as the measurement of the oil density. It is an indication regarding the grade of oil by comparing one oil to another. It is determined by a hydrometer that floats in the oil and the gravity is read on the scale of the hydrometer at the surface of the oil.

How are oils classified?

Oils are normally classified according to their viscosity. The SAE( Society of Automotive Engineers) has assigned a number to an oil whose viscosity at a certain temperature falls within a range.

There are two defining temperatures used, namely -18C and 99C. SAE, 5W, 10W, and 20W grades are defined in terms of viscosity at -18C and are the oils that render starting an engine in cold weather easy.

SAE, 20, 30, 40, and 50 grades are defined in terms of viscosity at 99C and work satisfactorily in normal and hot climates.

Multigrade oils are oils that have the ability to develop multiple viscosities at different temperatures. This means that oil can be in SAE 30 grade at 99C and in the SAE 10W grade at -18C. Other possible multi grades include 5W/20, 20W/20, 20W/40, etc.

These are the following benefits of multi-grade oils:

  • No need to change oil according to the ambient temperature
  • Increased battery life
  • Longer engine life
  • Easy starting
  • Short warm-up period
  • Reduced oil consumption

Research has shown the differences between monograde and multigrade oils for a car engine.

Conclusion

This blog post addressed the question, ‘What is the car engine oil capacity?’

We understood the importance of oil in a car engine and came across the necessary properties an engine oil needs to possess to help the engine perform optimally. Furthermore, the classification of oils has also been discussed. Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): What is the car engine oil capacity?

How much Oil Stop Leak should I use?

This is a useful additive to curb oil leaks and only about 20% of the total storage capacity should be used.

What are the most likely places for an oil leak?

The most likely places for an oil leak include the valve cover gaskets, spark plug tube seals, oil pans, and oil filters.

How long does Lucas Oil Stop leak take?

The Lucas Oil Stop leak takes about 500 miles to completely seal the oil leak. It is important to keep the engine oil levels in check until the process is completed.

References

https://addinol.de/en/products/lubricants-for-the-automotive-sector/engine-oil/multigrade-oil/

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