1. Combustion Byproducts: During the combustion process in the engine, small amounts of unburned fuel, soot, and other particles escape past the piston rings and enter the oil. These contaminants cause the oil to turn darker over time.
2. Oxidation: Motor oil is exposed to high temperatures and oxygen inside the engine, which can lead to oxidation. This chemical reaction causes the oil molecules to break down and form various oxidized compounds, which contribute to the oil's darkening color.
3. Wear and Tear: As the engine's components, such as pistons, bearings, and camshafts, rub against each other, tiny metal particles are generated due to wear and tear. These metal particles get suspended in the oil, giving it a darker appearance.
4. Additives: Many motor oils contain additives that are designed to improve their performance and protect the engine. Some of these additives, such as detergents and dispersants, help keep contaminants suspended in the oil, preventing them from settling down and forming sludge. The presence of these additives can also contribute to the oil's darker color.
It's essential to follow the recommended oil change intervals specified by the vehicle manufacturer to maintain the oil's effectiveness and prevent any potential harm to the engine.
