A diesel engine in good condition shouldn’t be producing visible smoke from the exhaust. When a diesel truck is accelerating under load, a short puff of smoke can be fine, especially in older diesel engines, but anything more than this can be cause for concern. Diesel smoke is almost always an indication that there is some sort of problem in your diesel engine. Some of these possible problems are more serious than others. The color of the diesel smoke can often help you know what the problem likely is, so you should always take note of it. Diesel smoke is usually either gray/blue, white, or black. Here are some of the most common causes of the different colors of diesel smoke as well as their solutions.

Is Your Engine Blowing Blue or Gray Diesel Smoke?

Blue smoke usually means that your diesel engine is burning oil. Is your diesel truck emitting blue/gray smoke from the exhaust during startup or heavy acceleration? Do you notice a burnt oil smell while you are accelerating? These are all indications of a diesel engine burning oil. Don’t make the mistake of assuming that you are only burning oil if your oil light is on. In most vehicles, this light only comes on when the problem has reached the point where you need to shut your engine off immediately.

Some of the common causes of burning oil are issues with piston rings, PCV valves, valve seals, turbo seals, and injector O-rings. Solving the problem is as simple as finding its origin and getting that component repaired or replaced. Bring your diesel truck to a mechanic and tell them the color of the smoke and that you think your diesel engine is burning oil. A diesel mechanic will be able to find the source of your burning oil problem and fix it for you before it causes serious damage to your diesel engine.

What Does White Diesel Smoke Mean?

You don’t want to see white diesel smoke coming from your exhaust. Thin, white smoke that goes away quickly is only condensation and does not indicate a problem. However, thick, long-lasting white smoke can tell you that there is a serious issue. White diesel smoke most likely means that your diesel truck is burning coolant. This can be caused by a cracked engine block, blown head gasket, or damaged cylinder head. All of these problems are serious and can be quite costly. Another reason a diesel engine may be emitting white smoke is if the fuel is passing through the engine and reaching the exhaust without being burned. This can be the result of an engine that is too cool for burning fuel, fuel injection timing issues, low compression in cylinders, burnt out glow plugs, clogged air filter, defective fuel injector, or low-quality fuel.

You should bring your diesel truck to a mechanic if it is emitting white smoke. They will be able to determine what is causing the smoke and then provide you with a solution. A diesel mechanic is especially necessary if the cause is due to damage in the engine. A cracked engine block, blown head gasket, or damaged cylinder head should be found and fixed quickly to avoid further damage to your diesel engine. Some of the other possible causes can be solved on your own if you know the exact origin of the problem. For example, cleaning your fuel system can resolve many issues between the tank and the injectors. Adding an automatic pre-heater can help bring the temperature up for properly burning fuel. Because some of the causes of white diesel smoke are more troublesome than others, you should have a diesel mechanic help you find the cause. You don’t want to try to fix it on your own and then find out after it’s already too late that you fixed the wrong component.

Is Your Truck Emitting Black Diesel Smoke?

Black diesel smoke is often referred to as “rolling coal.” Some diesel truck owners add tuners, modules, smoke switches, or larger injectors to make their diesel engine burn more fuel than necessary in order to purposely create clouds of black smoke. If you do something like this, then you obviously don’t need to worry about the presence of black diesel smoke. However, if you aren’t purposely creating black smoke and still see it coming from your exhaust, then you may have a problem on your hands. A small amount of black diesel smoke is normal for a well-functioning diesel engine. However, a lot of black smoke at the wrong RPMs and loads can indicate that there is a problem.

There are a lot of different possible causes of black diesel smoke. They can include incorrect timing or air/fuel ratio, worn turbocharger, dirty intake manifold, dirty injectors, common rail injectors remaining open too long, clogged air filter, poor fuel quality, low cylinder compression, or too much carbon buildup in the combustion chamber. A diesel mechanic will be able to help you figure out the exact cause of your black diesel smoke. Cleaning out fuel injectors or replacing the air filter may be simple solutions to the problem. More complex solutions may include checking your intake manifold, replacing your turbocharger, or adjusting your air/fuel ratio. A diesel mechanic will be able to provide you with the right solution to fix your diesel engine’s problem.

Get the Help of a Trusted Diesel Mechanic

When your diesel truck emits smoke of any color, you should pay attention. Any color of diesel smoke can indicate a problem with your diesel engine. When you start to notice smoke that isn’t normal for your truck, you should have a diesel mechanic check for any problems. Because some of the issues that can cause diesel smoke can be quite serious and harmful for your diesel engine, you should seek the help of a diesel mechanic as soon as possible. When you bring your diesel truck to a mechanic, make sure you tell them the color of the smoke so that they know where to start looking for the cause. Certified Diesel Solutions is Knoxville’s best automotive and diesel mechanic. Our experienced mechanics are ASE certified and use the latest tools and diagnostics equipment, which enables us to handle all types of repairs and maintenance services on all makes and models. You can trust us to find the root of your problem and solve it the right way. Reach out to us today at 865-964-6598 or online to schedule service.