• 4min

Tasks of the motor oil

#Vintage Cars

Did you know what functions the engine oil in your vehicle actually has? We explain what it is there for, why it is important to change it regularly and why you should always use the right engine oil for your vehicle.


Motor oil lubricates mechanical engine components. As a result, it reduces friction between moving components (preventing metal-to-metal contact) and thus wear and damage to the engine.


Motor oil helps to cool the engine components. It ensures heat dissipation in the engine so that it does not overheat.


Motor oil cleans the engine. Combustion residues, metallic abrasion and deposits are absorbed by the oil and transported to the oil filter.


Motor oil helps to seal the piston rings to the combustion chamber and thus prevents pollutants from entering the oil circuit.

Corrosion protection

Engine oil forms a protective film over the metallic surfaces. This prevents exposure to air and condensation and protects the engine from some aggressive combustion products.

Why does the engine oil need to be changed?

Motor oil consumes and contaminates itself over time. For example, due to combustion in the engine, dilution with fuel or condensation, natural oil aging and mechanical abrasion.

Only a regular oil change, i.e. replacing the old, used oil with new oil, ensures reliable engine function and increases the service life of the engine.

The perfect oil change consists of:

  1. Motor flush
  2. Oil change
  3. Wear protection additive

All dirt and deposits inside the engine are removed by flushing the engine with Motor Clean before the oil change. The used oil is then completely removed from the oil circuit by draining. Because only in a clean engine can the fresh motor oil achieve its full performance. The engine then runs even more effectively, quieter and is more economical in consumption.

To ensure optimum long-lasting protection, we recommend adding the wear protection additive Cera Tec to the fresh engine oil when changing the oil. Thanks to the smooth-running effect, it also reduces friction, wear and fuel consumption and thus also increases the service life of the engine.

Why is it important to use the right motor oil?

Every engine design has its own characteristics and therefore also specific requirements for the motor oil. Excessive wear and reduced efficiency can be expected if an oil with specifications outside the required values is used. Using an oil with the wrong viscosity can affect the timing of variable valve control systems and/or lead to increased fuel consumption due to lower engine efficiency.

For this reason, it is essential to observe the manufacturer’s approval for your vehicle when selecting the motor oil. Because only an oil approved by the manufacturer guarantees optimal function, full protection and engine efficiency, while at the same time ensuring that components of the emission system, such as catalytic converters and particulate filters, can operate without loss of efficiency.

In addition, you should always use high-quality motor oils. These ensure that they perform optimally both during cold starts and at maximum operating temperatures. And this in response to the constantly increasing demands of modern engines and sometimes very long oil change intervals. Moreover, using a high-quality oil can also help further reduce internal friction while maximizing performance and efficiency. Modern oils reduce fuel consumption and therefore the associated pollutant emissions, too. What is more, modern engine oils do not contain chlorine or heavy metals and can be easily reprocessed and reused.

Our modern engine oils are both high-quality and officially approved by many manufacturers. Often, they even exceed the manufacturer’s specifications.

Which oil is right for your car?

We give your engine exactly what it needs: Top quality made in Germany with Germany’s most popular lubricant brand*.

When it comes to oil, LIQUI MOLY is your best choice. Use our oil guide to find the right motor oil and other suitable operating fluids for every vehicle.

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* For years now, readers of Germany’s leading car magazines have voted LIQUI MOLY the best lubricant brand.

More answers to your questions

Do you have any unanswered questions about motor oil? Take a look at our FAQs. You may find the correct answer there. Alternatively, our technical advice is of course always available to you in person.

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