How to know your engine oil by its color

Caring for one’s car starts with checking one’s oil regularly and following the recommended oil change intervals. Did you know that methodical oil changes can help clean the engine, lubricate its moving parts, prevent corrosion and rust, and extend the life of one’s engine?

To get a quick insight into one’s car’s health, remember to check the level, consistency, and color of one’s motor oil as it gives clues to the health of one’s engine, including helping spot potential issues like engine oil contamination and leaks.

Though color on its own does not indicate oil performance, often a lubricant color change can be a cause for concern, as it often shows the oil's composition or chemistry has been changed, but one must first consider the lubricant's original color. New lubricants usually have a color that is related to their viscosity and formula. Certain additives and dyes can affect the original base stock color. Contamination is another common reason a lubricant changes color, with the oil becoming darker if there is lubricant cross-contamination or solid particles from the environment. If the same lubricant is used in several machines and all of them show a progressive change in oil color, this likely would show natural lubricant ageing.

While some shades of motor oil may help one figure out potential problems, color alone cannot be used as a DIY diagnostic tool. In fact, a gradual darkening of the engine oil is normal and actually indicates that the engine oil is working as expected by cleaning the engine and carrying the deposits and sludge.

To check the engine's oil color, here are some steps one needs to follow:

• Park your car on flat ground and let the engine cool for 10 or 15 minutes. Keep gloves or paper towel or a rag handy. Ensure that these are free of dirt to avoid introducing external contaminants into the oil.
• Next, pop the hood and locate the oil dipstick, it typically has a plastic orange or red pull tab. If you’re having trouble locating it, consult your vehicle’s manual. 
• Once located, pull the dipstick out, wipe it clean with a clean paper towel or rag, then place it back into its tube without introducing external contaminants. Then pull it out once more and look at the oil level, color, and viscosity.
• Use the below yardsticks to get an idea of the color of one’s engine oil.
• Clean engine oil can appear in different shades of amber (unless it has been dyed), depending on the type of oil in your car and the age of your vehicle.
• Engine oil that's turned from a dark shade of amber to black could be a sign that your oil is old, especially if it is thick or sludgy.
• Brown or greyish engine oil with a foamy consistency can be a sign of contamination from a coolant leak or a signal that the engine idles excessively and rarely reaches operating temperature.
• Humid conditions can cause condensation buildup and surface rust on your metal dipstick, resulting in a rust-colored reading when checking motor oil.
• A reddish appearance in the oil might also show automatic transmission fluid though some engine oils could be dyed red too.

In the end, one needs to remember that color is not the only sign of engine oil health; it’s particularly important to note color changes in your engine oil, especially when combined with fluctuations in oil consistency and volume, as they can give you an insight into oil-related challenges.