Maintaining your BMW involves a lot, and one of the most basic yet significant is checking your motor oil. Have you ever changed or checked the oil in your BMW and noticed that it is black? You might be wondering what it means. Is it something to worry about? Is it worth going to the mechanic right away? Let’s get to the bottom of why your BMW motor oil is black and what you should do.
Why Motor Oil Turns Black
- Normal Use: The longer you use motor oil, the darker it will be since it collects particles while it is running through the engine. This is the normal process and it is a sign that the oil is doing its function of cleaning the engine. While the oil is circulated through the engine, it picks up small pieces of grime, shavings, and other impurities, and those impurities cause the oil to darken.
- Contaminants: Dirt, soot, and other particles can make their way into the oil especially if the air filter or oil filter doesn’t function properly. These filters are supposed to prevent clogged particles or dust from settling on the oil. If they fail to do their work, the blackening of the oil will be accelerated.
- Heat and Oxidation: The engine produces a lot of heat which can cause the oil to oxidize and degrade after every engine run time. This oxidation causes the oil to turn blackish gradually. The high temperatures along with the oxidation of oil molecules are one of the reasons for the oil turning black in color.
- Additives: There are many types of additives in modern motor oils that improve the oil’s performance. These additives serve the purpose of cleaning the engine, reducing friction, and preventing corrosion. While these additives do their job, they also can make the oil darken. The cleaning agents in the oil, for example, lift dirt and sludge from the engine parts, and then, these particles mix with the oil, which makes it turn black.
When to Be Worried about Black Motor Oil
- Thick or Sludgy Oil: If the motor oil that you are checking is no longer just black and smooth, but rather thick and sludgy, it may be a sign that it has been in the engine for too long, and is beginning to break down. This means that the oil will be unable to provide lubrication for the moving parts of the engine which can make the engine performance
- Foamy or Milky Oil: If your oil appears to be frothy or whitish, it is a warning signal of a coolant being mixed into the engine oil. In this case, seepage can result from a broken head gasket, engine block, or cylinder head. The oil gets mixed with the coolant, which can do detrimental damage to the engine. This is a major problem that needs to be dealt with urgently in order not to cause engine failure that could be catastrophic.
What Should You Do When You See Black Oil
When you come across dark oil in your car, more often than not, it’s time for an oil change. Check the recommended maintenance schedule for your vehicle and compare it with the current mileage.
If you can not remember the last time you changed your oil or the oil appears thick, sludge-like, or smells like burning, then go to a mechanic for an inspection. These symptoms suggest an engine that needs prompt attention. Oil checks are a regular practice and oil changes should be done on time to keep the engine running smoothly and efficiently.
Bring Your BMW To Momentum Motorworks
At Momentum Motorworks, we are 100% reliable 
when you need to repair and service your BMW car; we serve Birmingham, AL, and nearby cities. Our dedicated personnel will be on standby to deal with any issue you might be facing. If you need to do regular maintenance like an oil change or you have some issues to solve in your car, just come down to our workshop. We will ensure that high quality motor oil that meets your BMW specification is used to replace the old oil. Our services are available for residents from all over Alabaster, Homewood, Helena, Hoover, Mountain Brook, Vestavia, and Birmingham, AL. You can make an appointment by calling 205-403-4626.