Causes of Diesel Engine Smoke By Color

Discover The Causes of Diesel Engine Smoke By Color

Why is my diesel engine smoking? What are the causes of my diesel engine smoke and its changing color? If these questions are on your mind, this guide is definitely for you. 

When it comes to driving, we all understand specific colors. Red means “stop,” Yellow means “caution,” and Green means “go,” right? Changing traffic lights’ colors is obvious, but what happens if the smoke from your car’s diesel engine changes shades? 

When detecting problems in your diesel engine and turbocharger, it is crucial to observe the color of your exhaust smoke. Any variations from the original color can be early indicators of problems like oil leakage, a faulty turbocharger, a clogged air filter, etc. 

Diesel engine smoke is mainly detected in three colors: white, blue, and black. Constant smoke from the exhaust points to a deeper internal problem with the engine. Simultaneously a tiny gust of smoke during acceleration is acceptable with older diesel engines. 

Seeing smoke in different colors from a diesel engine is a common sight for many car owners. However, this smoke could indicate an issue with your diesel engine that requires your attention.

 Causes of Diesel Engine Smoke By Color

  • White Smoke from Exhaust

White Smoke from Exhaust

White diesel smoke can sometimes signal more significant problems with your engine. Be careful of this white smoke, as it may irritate your skin and eyes. 

Suppose white smoke from exhaust occurs in freezing temperatures during a startup and goes away instantly. In that case, it usually indicates frozen deposits of soot around the rings which expand and then burn away once the engine gets warmed up. 

Following are some of the causes of diesel engine white smoke:

  • Causes of White Smoke from Exhaust-

If you see a thin white smoke that quickly fades away, it may be a form of condensation. However, longer-lasting and thicker white smoke indicate more significant problems you must address ASAP. 

One common cause of white smoke is that your engine might have issues with burning the coolant. This problem usually occurs because of a crack in the engine block, the cylinder head is damaged, or the head gasket has blown.

White smoke can also signify fuel passing through the engine and reaching the exhaust without being burned. A few other reasons behind this problem could be low compression in the cylinder, a machine that isn’t hot enough for the fuel to burn, issues with the fuel injectors, burnt-out glow-plugs, a clogged air filter, or the use of low-quality fuel.

Faulty Injection Timing, Damaged Crankshaft Keyway, Damaged Timing Gear, Damaged Fuel Lines, Damaged Rings or Cylinder Liners, Low Fuel Pressure to the Fuel Pump, and Damaged or Incorrect Fuel Pump Timing might sometimes also lead to white smoke.

  • Blue or Grey Smoke from Exhaust

Blue or Grey Smoke from Exhaust

Blue engine smoke is the rarest smoke stemming from a diesel engine. If you’re noticing blue or greyish smoke coming from your machine, there are a few possible reasons. Let’s discover some of the most common causes of blue or grey diesel smoke.

  • Causes of Blue or Grey Smoke from Exhaust-

Blue or greyish-white smoke from the exhaust usually means you must look at the oil. Witnessing a burnt-oil smell or noticing blue or grey smoke leave your exhaust on starting your vehicle or heavy acceleration are common signs that the oil is burning. 

Blue smoke is common when starting an engine in cold weather. The oil thins out and gets burnt while escaping into the cylinder due to the cold temperature. 

Some other common causes of blue or grey exhaust smoke include valve seals, poor seals on piston rings, injector o-rings, PCV valves, or turbo seals.

  • Black Smoke from Exhaust

Unlike white smoke, Black smoke contains particles of a high concentration of carbon exhaust. The combustion of diesel fuel breaks down the long chain of carbon molecules into smaller molecular chains in the cylinders. The byproduct combines carbon dioxide and water when the exhaust leaves the engine. 

Black smoke is the most common diesel engine smoke color that likely indicates something is wrong during the combustion of diesel fuel. Black smoke, also called “rolling coal” could have several causes. Let’s take a closer look at some of them.

  • Causes of Black Smoke from Exhaust-

You can expect a little black smoke on a properly functioning diesel engine, and that’s normal. However, it’s a good idea to watch the amount of black smoke at different RPMs (Revolution per minute) and loads to tell if something is wrong.

A worn turbocharger, incorrect timing or air/fuel ratio, dirty intake manifold or clogged air cleaner, dirty rail injectors open for too long, poor quality fuel, low cylinder compression, or excessive carbon buildup in the combustion chamber can all be common causes of diesel engine smoke.

No matter the color, the causes of diesel engine smoke are something you should not ignore. A properly maintained and working diesel engine should produce no visible smoke. 

#Pro Tips: Make sure to shut down the engine instantly if you encounter excessive smoke, as additional heat or load could severely damage your engine.

Hot Shot Secret to Eliminate the Causes of Diesel Engine Smoke by Color

Identifying the causes of diesel engine smoke by color can be tricky. Therefore, you must consult professionals who can find solutions to help you treat the root cause and eliminate smoke, so you don’t have to face such issues again. 

Diesel Components Inc. is the one-stop solution for your car. We own and provide equipment, service, parts, and technical support to the entire North America and countries worldwide. 

We’ve got the right parts and experts to repair the ultimate causes of your diesel engine smoke by color. If you’re anywhere near Burnsville, Minnesota, we are just a drive away, or you can even call us to book an appointment today.