Should You be Concerned About Smoke Coming Out of Your Vehicle’s Tailpipe?

Posted on October 24, 2022 by Carson Wileman

Smoke coming from the tailpipe of your vehicle can be either dismissable or a bad sign. It can mean absolutely nothing or represent potentially serious problems with your vehicle’s engine or the parts within it. One way you can begin to narrow down the source and cause of this smoke is by the color and odor of the smoke.

Some of the issues which can cause smoke to be expelled from the exhaust are oil leaks from many possible engine components, coolant leak, air leak, or damage to the engine’s hardware such as a cracked exhaust manifold. Even electrical or technological issues can indirectly cause smoke, as a result of the vehicle’s computer miscalculating when and how much air or fuel should be injected into the engine. The system has to work harder to compensate for such an issue and can cause the expulsion of smoke in various colors.

Basic Engine Airflow

The exhaust of your vehicle is a part of the engine system that regulates the flow of gases throughout the engine during vehicle operation. Air is injected into the engine when it is ignited in order to create a combustion event to start the vehicle. From there, as the vehicle operates, a specific air-to-fuel ratio must be maintained to keep the engine running smoothly.

To keep this balance, a part of the engine called the exhaust manifold gathers the gases flowing from the engine’s cylinders and directs them into the collector pipe to be expelled from the exhaust. These gases are known as waste gases and can be harmful to the performance of the engine if they remain in the system. The presence of these waste gases is also dangerous in that it increases the risk of combustion due to the excess air inside the engine.

Possible Colors of Smoke and Their Causes

When smoke is being expelled from the tailpipe, it could be an indication that something is not doing its job in the engine. The smoke can come from fluids leaking and mixing with gases in the engine due to a crack or from your vehicle being overworked in trying to compensate for some miscalculation. It may not always be indicative of a real problem. Still, you can begin to narrow down the causes by paying attention to the color of the smoke.

Colors of smoke that may come out of the exhaust include blue, grey, white, and black. If you happen to see smoke coming from your engine that is white in color but only happens in the mornings or on cold days, there is no need to worry. This “smoke” is actually just condensation turning into water vapor as your engine heats up.

White Smoke

White smoke can be indicative of a problem with leaking coolant. Although it is not severe in nature, a coolant leak in your vehicle will cause smoke as the coolant flows onto hot parts of the engine and essentially goes up in steam. Leaking coolant can be caused by a cracked engine component, namely a head gasket or cylinder head.

This is something that you should get checked as soon as possible because this can lead to more serious issues with your engine, as it is now more susceptible to overheating. This smoke will always come with a strange smell in the cabin of the vehicle.

Blue or Grey Smoke

Smoke colored either blue or grey is a sign of something more serious going on in your engine. These colors are likely to be the symptom of an oil leak. The oil is leaking onto internal components and heating up. The oil then burns and creates either of these colors along with a strong smell of gasoline.

There are many reasons why oil may be leaking into or from your engine. It could be a hardware problem, such as broken or worn valve seals, or a mixture of electrical and hardware issues like a faulty oil pressure switch or mass airflow sensor causing malfunctions for fuel and oil injection. The cause can also be determined by noting whether the smoke is emitted during acceleration or deceleration.

Black Smoke

Black smoke can tell you that your engine is burning either too much fuel or there is an internal oil leak. Too much fuel can also be caused by a dual mechanical and technological failure like a faulty high-pressure fuel pump causing miscalculations for fuel injection or due to oil residue mixing with water vapor as it exits the engine.

This color is also a sign that there is something potentially serious going on with your vehicle’s engine and needs to be looked at by a professional as soon as possible.

Schedule an Appointment With the Experts

If you have noticed smoke coming from your tailpipe in any of the colors above, schedule an appointment with an expert mechanic as soon as possible. The issues causing the smoke can range anywhere between minimal to severe, and you need to be sure that your mechanic can confidently and accurately diagnose it.

At Keith Cox Autobahn, we are focused not only on the optimal performance of your vehicle but your safety as well. With decades of experience under our belt, you can trust that our family-owned and operated service center can exceed your maintenance and repair standards. Schedule an appointment with our experienced staff in Bellingham, WA.