Dirty oil is typically dark brown or black.
When engine oil is new, it often has an amber or light brown color. As it circulates through the engine, it picks up contaminants such as dirt, debris, and byproducts of combustion. Exposure to high temperatures also causes the oil to break down and oxidize. This process leads to a darkening of the oil's color.
Here's a breakdown of what different oil colors might indicate:
- Light Amber/Brown (New Oil): This is the color of fresh, clean oil.
- Brown: Oil is starting to get dirty and has been in use for a while. This is normal.
- Dark Brown/Black: The oil is dirty, heavily contaminated, and/or has been exposed to excessive heat. It's a sign that an oil change is needed soon or is already overdue.
- Milky/Light Brown: This could indicate the presence of coolant in the oil, which is a serious problem.
Therefore, if your oil is a dark brown or black color, it's a clear indicator that it's time for an oil change to ensure optimal engine performance and longevity.
