Why is Diesel oil black?
One hundred years ago in 1908, Rudolf Diesel and his new engine technology were put into the first car and later and small trucks. Today millions of diesel cars, vans, trucks, trains and ships are going around handling almost all of the world's distribution of goods. But all of these diesels have one thing in common Black diesel oil.
Don't worry pulling your dipstick to find really black diesel engine oil is not a bad sign. You do not have to worry about your diesel engine's condition or hastily schedule an oil change.
We will now explain the reasons why a diesel's engine oil turns black quickly, even after a fresh oil change. The number one reason is that during the diesel burning process a small portion of sud which are hydro carbons better known as charcoal make their way down around the piston and piston rings into the engine oil. This is by design and does not prove that an engine might be worn, so when we purchase new Sprinter Vans it takes only about 2,000 miles for a brand new engine to turn its engine oil pitch black.
The second reason why the oil might turn black right after an oil change is because small amounts of the last engine oil is still sitting in the oil filter housing and other corners of the engine and will turn your brand new 15W40 or whatever new oil that goes in there just as black as the last oil you had drained.
Black engine oil does no harm to your engine. Diesels have engine oil filters and special oil additives that will handle the discoloring of its oil just fine. The larger carbon particles will be filtered out by the oil-filter and the additives in the oil hold the micro carbon particles securely in the oil and surround them by a smooth oil film until your next oil change becomes necessary.
Changing the oil in diesel engines is not needed as often as in gas engines. Although gas engines need oil changes every 3,000 to 5,000 miles, diesel engines are often double that. For example, a Mercedes Benz Sprinter Van has approximate oil change intervals of every 10,000 miles or so. The 2014 Sprinter vans actually have oil change intervals of approximately 15,000 miles.
So do not worry about what color your oil may be, just check that the oil level is between the suggested parameters on the oil dipstick and look for a note when the last oil change took place.