Why does the motor oil need to be changed regulary?

The motor oil costs only a small fraction of the total amount that you spend on your car but choosing the right oil can save you large sums. Low quality or overused motor oil is not capable of fulfilling its duties and can cause a series of problems. We are going to introduce the most important motor oil related problems, their usual causes and consequences.

Deposit formation

Possible reasons: additive depletion or contaminated motor oil.
Possible consequences: pre-ignition, reduced power, higher emissions.

Wear

Possible reasons: abrasive physical particles in the motor oil, additive depletion, motor oil contamination or too low motor oil level.
Possible consequences: engine component failure or engine breakdown.

Motor Oil Viscosity Increase

Possible reasons: additive depletion, motor oil oxidation and motor oil contamination.
Possible consequences: motor oil circulation problems, wear of critical engine components, mechanical problems.

Motor Oil Thermal Breakdown

Possible reasons: additive depletion, motor oil oxidation, abnormally high engine temperature.
Possible consequences: motor oil thickening, oil starvation, cold start problems, engine failure.

Motor Oil Circulation Problems

Possible reasons: motor oil pump malfunction, clogged oil passages, too low oil level.
Possible consequences: low motor oil pressure, wear of critical engine components, mechanical problems.

How to Avoid These Problems?

These problems can be avoided by using quality motor oils and by respecting the factory recommended oil drain intervals. A quality motor oil contains all the additives that are required to prevent these problems so there is no need for aftermarket additives, for engine flush or for changing the oil more frequently than recommended by the OEM. An exception from the last rule is when the operating conditions are tougher than normal, since those conditions require the shortening of the oil drain interval.