My engine oil looks green

At times, the green color in engine oil could mean nothing, or it could be an indicator of a problem that requires fixing. It is crucial to determine why your engine oil is green before it causes irreparable damage to your engine.

Engine oil color guide

When your engine oil changes color, consider it as an unofficial means of communication whereby you understand what is going on inside and outside of your vehicle. Here are some oil color variations and what it means about your motor’s health.

Black and thick engine oil

what does it mean when your engine oil turns black

The original color of fresh oil is light-amber, the same color as beer. Once you drive your car for several miles, you may notice the color of your engine oil is somewhat darker. The longer your drive, the darker the oil becomes.

Modern oil consists of many detergent additives that enhance its performance. When engine oil becomes black, it means the additives have been filtered out, and the black color comes from them being in suspension in the oil. Once it thickens, consider it as a sign of saturation and that it needs to be changed soon.

Muddy brown or creamy engine oil

When engine oil is milky or brownish, it is a sign of a severe problem in your engine. This oil color variation indicates that the oil has, in some way, mixed with antifreeze from the cooling system. Often, this is due to a failure in the vehicle’s head gasket.

Once you take note of this unusual color, check your overflow reservoir or radiator to see if it is low. Many at times, this oil color is accompanied by white smoke from your exhaust. If your radiator or overflow reservoir still has the appropriate levels of fluid and there is no white smoke, but your engine oil is still creamy or brownish, you may consider water contamination.

Red engine oil

What Causes Black Motor Oil

If your engine oil has a reddish hue, it means that power steering fluid, transmission fluid or engine coolant has made its way to mixing with your engine oil. In turn, this could mean there is a problem with your power steering pump, transmission process, or cooling system.

It is advisable to visit your local repair shop for a mechanic to determine the exact problem and fix it. The smell of the engine oil is also an indicator of the problem. If it smells sweet like maple syrup, it is coolant. If it smells like burnt marshmallow, it is power steering fluid. If it has a normal petroleum smell, it is transmission fluid.

Green engine oil

It is quite easy to notice brightly colored engine oil. Often, once it changes to bright green, the cause is likely to be your coolant is leaking into the oil. Coolant leaks bring into question the vehicle’s age. Older cars use more coolant when the engine overheats as compared to newer cars. Newer cars recycle the overused coolant; hence, they should not leak to the ground or mix in with the motor oil. Green engine oil in your older car should not make you panic. However, if it is a modern vehicle, you need to take it for further investigation.

On the other hand, green engine oil could also indicate diesel fuel has gotten into your oil. In most cases, it usually causes the oil to become thin. If fuel is in your oil, your vehicle’s injector or its fuel injection pump could be leaking. For repairs, it is best to seek out your mechanic.

What is green oil?

recycled motor oil

Green oil is oil made from recycled motor oil using special technology that produces new base oil. Annually, drivers in the United States use about 1.3 billion gallons of motor oil. Despite our many oil reservoirs all around the world, there is still a shortage of the product.

As such, green oil makes use of the improperly disposed of oil by reclaiming it, thus preventing its adverse effects on our environment. By converting this oil to green oil, the toll on non-renewable natural resources reduces, improving the fuel economy, without compromising the protection of your engine.


Oil color variation does not necessarily mean something is wrong with your engine. Engine oil can be very dark but still very useful in its function. It is also crucial to monitor the oil light on your dashboard to easily notice when your vehicle needs an oil change.

If your engine oil has different oil variations, it is time to schedule an appointment at your repair shop. Oil color variations are one of the best indicators of what is happening in your engine.

There are several methods you may use to check your oil. You may opt to use a dipstick every few days or trace dyes with ultraviolet light, as used by professionals. By closely monitoring the color of your oil, chances of understanding the issue and fixing it, before it results in irreparable damage, are exponentially high.

If you are losing sleep over why your engine oil is green, it is best to consult your mechanic as soon as possible. However, in an older car, green engine oil is not necessarily a cause of worry.

Modern car owners with green engine oil should schedule an immediate appointment with their mechanic. Motor oil color variations can be a source of concern, but the sooner you find out why the color has changed, the better for your vehicle’s engine and overall performance.

Leave a Comment