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3 Common Types of Exhaust Smoke

Can you see visible smoke flowing from your vehicle's exhaust system? If so, you may have an issue as relatively minor as overfilling the crankcase with oil to as major as a cracked engine block. Check out these three common types (and colors) of exhaust smoke, possible causes, and when you should take your car to the shop.

white exhaust smoke flowing from vehicle

1. Blue/Gray Smoke

If you've accidentally overfilled the crankcase with oil, expect to see a blue/gray exhaust smoke. This color indicates that your engine is burning excess oil somewhere. It could also indicate worn valve seals, piston rings, or cylinders that are allowing oil to leak and burn. A stuck PCV (positive crankcase ventilation) valve is another common culprit. If this valve gets stuck, oil will mix with gases inside the engine and create blue smoke.

2. Black Smoke

Black smoke indicates that unburnt fuel is escaping through your vehicle's exhaust. It might be something as simple as a clogged air filter messing up the air to fuel ratio. Faulty engine sensors, a faulty fuel pressure regulator, or a carburetor malfunction are other common causes. A leaky fuel injector allowing unburnt fuel to pass is something else to consider when your car starts spewing black smoke. If you've replaced your air filter and are still seeing black smoke, it may be time to visit your trusty local mechanic.

3. White Smoke

Thick white smoke, especially during milder temperatures, indicates a possible major issue with your car's engine. This kind of smoke suggests that water or coolant has somehow entered the combustion chamber. This can lead to major damage to the engine. A blown head gasket, a cracked cylinder head, or a cracked engine block is often the result. If you notice thick, white exhaust smoke, arrange to have your vehicle towed to a local automotive repair shop. Continuing to drive could risk more damage!

Let Us Handle Your Exhaust Problems

At Custom Complete Automotive, our certified technicians understand the importance of keeping your vehicle's exhaust system in tip-top shape and are experts in exhaust system maintenance and repair. To learn more about our exhaust repair services, or to schedule an appointment at one of our convenient locations, contact us today!


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About the Author
Eric Riddles

Eric Riddles is an ASE Certified Master Automobile Technician who has been working as an auto mechanic since 1998 and originally joined the team at Custom Complete Automotive in 2005. Eric has numerous certifications in various aspects of car repair and spent 10 years training the next generation of auto technicians at a local high school Auto Shop classroom.

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