Change in Engine Oil Color

Engine oils are lubricants that lubricate and protect your engine. These oils are distinguished by their amber colour. But often we need to be on the lookout for oil discolouration. 

The colour changes sometimes indicate a wide variety of problems. At the same time, we need to be aware of some changes that are not serious. 

Clean and brand new oils appear amber-coloured. But darker, dirtier and thicker engine oils are signs of an oil change. Other colour changes you need to be cautious of are milky and frothy or creamy engine oils. 

These are indicative of a coolant leaking from the head gasket along with other reasons which are harmful to the engine. 

What Causes Engine Oil Colour Change?

It is vital to note that oil discolouration is a result of changing oil chemistry due to internal as well as external factors. For example, the inclusion of additives, detergents and dyes can alter the colour of the base oil. On the other hand, exposure to higher operating temperature, oxidation, dirt and dust are some of the factors that change the colour of the oil. 

Most importantly, we need to know that the oil darkens in appearance over time. Higher temperatures result in faster oxidation. Inevitably, this decreases the life of the oil. 

Contamination of the oil also occurs due to dirt, dust and grime collected in the oil which leads to deterioration and underperformance of the engine. 

Degraded oil does not lubricate the moving parts and the bearing efficiently and higher temperatures may cause excessive damage to the engine if not changed during the recommended interval. 

This is why changes in colours should be properly examined and diagnosed to ensure the smooth operation of the engine.

Furthermore, it is good practice to do regular oil checks for any colour or consistency changes so you ensure a safe and hassle-free riding experience for your vehicle. 

change in engine oil colour

What Does The Colour Of Your Engine Oil Mean?

Amber/Red-Brown

As mentioned earlier, recently bought and clean engine oil is amber in colour. It has a red brownish tint. If this is the colour you observe on the dipstick, it means that the oil is well-functioning and operational. In short, no worries! If this is the case, you won’t have any problems until the oil change interval is up. 

Dark Brown, Black & Thick 

If your oil appears dark brown or closely the colour of black along with thick and dirty, this most probably means that you’re due for an engine oil change.

It lines to the change when both the colour and the consistency shows contamination of the oil.

A thickened, dark and dirty with a lot of grime oil will deteriorate the performance of the engine if kept unchanged.

In comparison, if you find the oil dark drown or black but still the consistency is thin and runny, it is most possibly not contaminated. This is a condition when your driving in hotter temperatures on a long duration trip or commute. 

Something to look out for is that synthetic oils have a darker colour but they are pure, semi-transparent and glassy in appearance. As compared to conventional mineral oils, certain additives in these oil function to collect dirt and grime.

If over time, this oil becomes thicker and closer to black, it is a warning that your engine requires an oil change. 

Milky/Frothy, Creamy

This discolouration is a sign of a leak of head gasket failure. If the engine oil creamy or milky oil, it is possible there is the coolant leaking into the oil due to a broken head gasket.

Other problems include issues in the intake manifold or gasket at the water pump. The oil appears milky and frothy textured when the coolant seeps into the oil. To some, this oil also appears to look like chocolate milk.

 To check if you have coolant in your oil, check the following things:

  1. Check Temperature Guage of Vehicle (Should not be too hot)
  2. Radiator Fluid Levels (While the engine is not warm)
  3. Bubbles in Radiator Coolant (While engine-running) 
  4. Check for White Smoke From Exhaust

These signs mean that there is a chance the coolant has mixed into the oil. The only solution to this problem is a quick trip to the mechanic for oil analysis. The earlier this is done, the better it will be for your engine.

Moreover, oil is probably creamy in appearance because it may have been tainted with water. This happens due to water seeping into the engine while it is used as a coolant or due to condensation.

It is best to still do the above checks and perform a diagnosis through your mechanic. If the oil is a light, yellowish foamy texture, it could be because of oil pan aeration. This happens when you overfill the engine with oil. 

Why Does My Engine Oil Turn Black?

At times, we might drive in extremely hot conditions which leads to a hot engine. When you observe the colour which is now darker but not thick, it is just a result of the heat. 

To cool down, it is best to give it some time off so that the colour goes back to its natural colour. The oil also turns black due to carbon. Oil filters prevent this but it tends to build up and causes the oil to go black. 

How do you know if you need your oil changed?

Clean and non-contaminated oil looks red-brownish and more amber in colour. Other than that, its consistency should be pure, runny, fluid or viscous depending upon the specific viscosity grade of the oil. However, we have already established that engine oil expires and degrades over time. 

When exposed to dirt, grime and dust, the oil’s composition, colour and consistency will alter. It turns darker, thicker, dirtier and has the pungent or soul smell. This means that you are up for a much-needed oil change. 

This depends very much on the recommended kilometres or miles you have completed to get the oil replaced. Every owner manual mentions the interval and you must maintain those time intervals for your bike or car or heavy vehicle so that your engine doesn’t suffer the consequences. 

It most likely around 4000kms or sometimes around 5000kms to 12000kms for more modern engines and vehicles. In addition, synthetic oils can increase the life of the oil and you can drive for more kilometres as compared to other kinds of engine oils.

 Because of their enhanced composition and additives, these oils can increase the life of the engine oil and provide superior performance in extreme conditions as well. 

Conclusion

It goes without saying that you need to be on the lookout for the appearance of your engine oil. Discolouration does signify some changes or effects in the oil which if not properly inspected cause more harm than good. 

Although some are bad, there are some that aren’t as serious and do not mean an oil change. Besides, your engine oil becoming darker should not be the only indication for an oil change. 

So, there are other reasons which should be taken into consideration. Lastly, it is wise to check the oil for colour and consistency on the dipstick so that you are maintaining safe, smooth and effective rides every day!