What color indicates engine oil needs to be changed?

[LaKimberly]

When the engine oil turns brown or black and becomes opaque, it indicates that it needs to be replaced. Fresh engine oil is light yellow and transparent. After being added to the engine, it gradually darkens due to carbon deposits from prolonged engine use, eventually turning slightly black. The oil will continue to change color with further use. Oil changes should be performed according to the maintenance schedule, whichever comes first between time intervals or mileage - typically every six months or 5,000 kilometers for most vehicles. Newer models often have longer intervals of six months, 7,500 kilometers, or even 10,000 kilometers. For family vehicles, changing the oil every six months is generally sufficient. Using counterfeit engine oil can easily lead to sludge formation, so it's crucial to choose oil with quality assurance.