The controversial engine light! Some say it can strike fear in the very heart of seasoned mechanics. By the way, one improperly disposed of galleon oil can contaminate one million gallons of drinking water. Off topic a bit, but it lets you know how critical it is to change and dispose of oil properly. Another thing that people assume is that dark is an automatic sign of old oil. However, that’s not always true.
There are different oils and textures. Dark oil, even oil that’ used, may still have useful life if it still flows easily. Then there are oil filters that are completely blocked with oil sludge. These are filters that have never been changed. The only thing that can result is an engine change. Changing the oil shouldn’t be debatable. If you’re low on change, save a few dollars at every opportunity. Your engine and bank account will love you for it.