Why Is My Car Smoking?

3 Types of Car Engine Smoke

What do you do when your engine starts smoking? Is my car safe to drive? There are actually 3 types of engine smoke your car might produce from under the hood. The mechanics at Chapel Hill Tire are here to provide further insight and answer your questions about engine smoke.

1: White Engine Smoke

White engine smoke is commonly caused by burning radiator fluid (also known as coolant or refrigerant). You might also notice a sickly sweet smell (often compared to that of butterscotch or maple syrup). Radiator fluid contains ethylene glycol, which is chemically similar to sugar compounds—causing a sweet smell when burning.

Is white engine smoke dangerous?

While it might smell sweet, the radiator fluid is toxic to ingest, according to the CDC. Thankfully, ethylene glycol cannot be absorbed well through the skin. You might notice eye or lung irritation when breathing it in, so it is best to limit your exposure.

As for your car, it can overheat without the cooling properties of your radiator and its fluid. You can read our guide to engine overheating here. In this case, it is best to visit a mechanic immediately to avoid further damage to your engine. If your engine begins to overheat, safely pull over and give it time to cool down.

2: Black Engine Smoke

Dark engine smoke is a sign of excessive or improperly burning fuel. Most commonly, this issue is caused by a fault somewhere in your fuel injection system.

Naturally, gasoline is highly combustible. If you fear your car is catching on fire, FEMA recommends you immediately:

• Safely pull over and turn off your car.
• Have all passengers exit the vehicle as quickly as possible.
• Get at least 100 feet away from the car to avoid harm from the flames and toxic fumes.
• Call 911.

Black engine smoke could also stem from an electrical issue in your vehicle. Even if your car is not on fire, approach black engine smoke with caution. Do not continue driving without consulting a mechanic for insight.

3: Blue or Gray Engine Smoke

Smoke with a blue hue indicates burning engine oil. Engine oil can burn when it is far overdue for a routine oil change—or if you have replaced this fluid with the wrong oil type. Oil may also burn if you have a failing part somewhere in your engine, including a broken valve, leaking seal, or faulty piston ring.

Engine oil is vital to keeping your vehicle protected. Burning oil indicates a severe and immediate risk to your engine.

Is my car safe to drive?

How safe your car is to drive will depend on the source of the smoke. This could be a sign that your car is long overdue for a routine oil change. However, it may also signify a deeper engine issue. If you are unsure of your car’s safety, it is best to have it towed to a mechanic.

Chapel Hill Tire: Mechanic Car Care in the Triangle

If you fear your car may be a safety hazard to yourself or others—call 911 immediately. However, most of these issues simply require the insight and care of a mechanic. The experts at Chapel Hill Tire are here to help. We can find the source of your engine’s problems and repair them for you.

Chapel Hill Tire proudly serves the Triangle with our 9 locations across Apex, Raleigh, Chapel Hill, Carrboro, and Durham. Our local mechanics also commonly serve surrounding communities, including Knightdale, Cary, Pittsboro, Wake Forest, Hillsborough, Morrisville, and beyond. We invite you to make your appointment, browse our promotions, or give us a call to get started today!

About the Author

Marc Pons

Marc Pons has served as President of Chapel Hill Tire since 1997, leading its growth from a single Chapel Hill tire shop to twelve locations across the Triangle offering comprehensive car care services. Under his leadership, Chapel Hill Tire has become a nationally recognized leader in the auto repair and tire industry, known for its values-based approach. Founded in 1953, the company has earned numerous accolades, including multiple “Best Places to Work” awards, including recognition from Tire Business Magazine and the Triangle Business Journal. Other awards include “Top Shop in North America” by Tire Review Magazine, and recognition for their commitment to sustainability. Chapel Hill Tire has also consistently earned “Best of” awards from both Durham Magazine and Chapel Hill Magazine. Marc, a UNC Chapel Hill alumnus, is proud to lead this respected local business.

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Why Is My Car Smoking?

Smoke coming from a vehicle is a bad sign. It could be a simple issue, but most likely there is something seriously wrong with your car.

It’s normal to see a small puff of white smoke coming from your tailpipe when starting your car after it sits overnight — it’s only water vapor. You may also see steam rising from under the hood on a rainy day as water burns off the radiator or exhaust so don’t stress over those car myths. But if you’re driving and notice smoke billowing from the engine or tailpipe, don’t panic — yet. Knowing what the color (or smell) of the smoke means may help you identify the cause and determine whether to stop immediately or keep driving to a repair shop.

What Makes a Car Smoke?

The most common cause of smoke under the hood is small amounts of motor oil or other fluids accidentally spilled or leaking from a bad gasket or seal onto a hot engine or the exhaust system. Those other fluids may include engine coolant, power steering, brake and transmission fluid, even window washer solvent. This smoke is usually harmless, but it needs to be addressed as soon as possible.

A cloud of smoke belching from the tailpipe or beneath the hood, however, usually means a serious mechanical or electrical failure.Here are some mechanics tricks that can be very helpful while dealing with car problems.

What Do the Different Colors (and Smells!) of Car Smoke Mean?

• White smoke from the tailpipe indicates coolant from a bad head gasket or another failed internal engine part is burning in the combustion chamber.
• A blown radiator hose spraying coolant onto a hot engine will also produce wispy white smoke that looks like steam. Smoking coolant has a sweet pungent odor and can feel oily if rubbed between your fingers.
• Blue or gray smoke and a pungent, bitter odor from the tailpipe signal the engine is burning oil. Possible causes are leaking valve seals, worn or seized piston rings, a plugged PCV valve, overfilling the crankcase, failing to change the oil regularly or using the wrong type of oil. Oil consumption without external leaks or blue smoke indicates oil is slowly burning in the engine. Try changing to a high-mileage or thicker motor oil.
• Transmission fluid sucked into the intake manifold from a defective transmission vacuum modulator will produce thick grayish smoke from the tailpipe.
• Black smoke usually means the vehicle is burning raw fuel. A leaking fuel injector, defective fuel pressure regulator, a failed engine sensor or ignition component results in incomplete combustion, which allows raw unburned fuel to make its way into the exhaust system and out the tailpipe. Black smoke from one of these conditions will smell like, well, gasoline. Until the issue is repaired, your vehicle will run poorly and have poor gas mileage, possibly even damaging the O2 sensor and catalytic converter.
• Black smoke from an electrical failure, or burned wires from a short circuit, can cause the lights to flicker or interfere with other electrical devices. It smells like burning plastic. With several hundred feet of wire and electrical devices tucked into every corner of a modern vehicle, smoke from an electrical failure can emanate from under the hood or the passenger compartment.

What Do If Your Car Is Smoking?

Pull over and determine if your car is safe to drive — use common sense, and always err on the side of caution. Look at the gauges and warning lights to see if the engine is overheating, if the oil light is on, if oil pressure is low or if the Check Engine light is on.

Do a quick visual inspection. You could have run over a plastic bag that is burning on the catalytic converter. Never touch or work on a hot engine. Wait until the engine cools down and check the fluids. However, if you see fluids dripping or puddles forming under the hood or on the ground, it’s time to call for a tow. You risk severe damage to your vehicle if it runs out of coolant, transmission fluid or motor oil, which will require extensive (and expensive!) repairs.

Bob Lacivita

Since rebuilding his first engine at age 14, cars have been Bob Lacivita’s passion, as well as his way of life. He went on to become an award-winning ASE and General Motors auto technician, vocational educator, career and technical center administrator, technical consultant and freelance writer; teaching legions of students and readers about DIY ca.

Why Is There White Smoke Coming From My Engine?

Have you ever been driving your car and seen white smoke coming from under the hood? This condition is scary and alarming, especially if you don’t know what is causing it. White smoke from the engine is not something that should occur under normal circumstances.

We look at the causes of white smoke from the engine and discuss possible solutions. We can also estimate what a repair might end up costing you.

What Causes White Smoke from Engine?

The most common cause of white smoke coming from the engine is an external coolant or oil leak. The external coolant leak could also come from an overheating engine, which pushes the coolant out of the system into the engine bay.

When your combustion engine is working the way it was intended, it produces a mixture of carbon dioxide and water vapor. This is channeled out through the exhaust system and mostly unnoticed. However, when there is a problem with the way the engine is running, it might start burning something else.

White smoke indicates some form of contamination. Instead of burning air and fuel, the engine is burning something else.

Here’s a more detailed list of why there is white smoke coming from your engine:

1. External Coolant Leak

If the white smoke is coming from the engine bay, you most likely have an external coolant leak or an overheating engine. When coolant comes in contact with the hot part, vapor will create white smoke.

Coolant leaks can be caused by a lot of different things like cracked coolant hoses or bad gaskets. If you can see a coolant leak, you can check out this article about coolant leaks to learn more.

White smoke from the engine bay can also be caused by an overheating engine, where the coolant is being pushed out of the coolant system. If the smoke is coming from the exhaust and not from the engine bay, the problem most likely lies elsewhere.

2. Blown Head Gasket

When the head gasket blows, coolant leaks into the engine compartment or into the exhaust pipe. If it is serious, the leak might be visible on the outside of the exhaust manifold. However, these problems often go unnoticed.

Still, it will create white smoke coming from the engine. It can also cause an overheating engine, which leads to extensive engine damage. This is one of the more costly repairs to perform but it is necessary if you want to save your motor.

3. Broken Cylinder Head

If a cylinder head cracks, coolant can leak into the cylinder or combustion chamber. As it mixes with the fuel, it will create the same white smoke seen with a blown head gasket.

If coolant is seeping into the engine, it can’t do its job, leaving your engine at risk of overheating. You should look in the oil or coolant reservoirs to see if there is any sign of the two mixing together.

4. Defective Fuel Injector

The injector ensures that there is the right amount of fuel to mix with oxygen for combustion. Most modern motors are highly calibrated to ensure nothing affects this mixture.

However, if the injector isn’t working right, the mixture might receive too much fuel. Because this fuel won’t be able to burn correctly, you will notice white or grey smoke coming from the exhaust.

5. Poor Diesel Injector Pump Timing

You can also have trouble with your diesel engine if the mixture isn’t just right. If the injector pump timing is wrong, it will act just like a faulty fuel injector from a gas engine.

The bad timing produces a mixture that contains too much fuel. As it goes unburned, you end up with white smoke pouring from the engine.

6. Leaking Seals/Valve

The engine is made of numerous seals and valves that must all do their job for everything to work right. If one of the piston valve seals or rings starts to go bad, oil can start leaking.

Smoke from burning oil tends to have more of a blue color to it, but it is easily mistaken for white smoke. It will appear whiter when the leak is minimal, eventually turning bluer as the leak gets worse.

3 Types of White Smoke from Engine

Thin Vapor

Your car typically produces some vapor as part of the exhaust. If you aren’t used to seeing it or you start your vehicle on a cold day, you might be more alarmed.

When temperatures drop, the exhaust steam can look more intense, sometimes being mistaken as smoke. However, if this smoke disappears quickly, you probably have nothing to worry about.

Sweet-Smelling Smoke

When the white smoke is thick and comes with a sweet smell, you can bet on a coolant leak. Coolant is very sweet. This is actually the reason you are told to keep antifreeze away from animals – they are attracted to it and drink it because of its sweet taste.

However, when coolant mixes with fuel, it burns in the engine, creating white smoke from the engine. It’s also going to produce a distinct sweet smell that is unlike any other automotive fluid. As we discussed above, a blown head gasket or cracked cylinder could cause this situation, both of which are costly repairs.

Normal White Smoke

If you notice white smoke coming from the engine, but you don’t smell anything unique, it could be caused by condensation in the exhaust. Just like regular water vapor, condensation can build up in the exhaust, especially if you are just starting the vehicle in the morning.

Picture dew forming on the grass. This is the same situation, but in your car exhaust. If this is the situation, it will burn up quickly. If the smoke persists, there is something wrong with your engine that should be looked at.

Engine Smoke Repair Costs

The cost to repair a fault resulting in white smoke varies depending on what is causing it. As we’ve illustrated, there are several conditions that could occur. If it is something simple like a bad gasket, a replacement should cost you less than $150, with labor included.

All of the other repairs tend to be pricey. For example, a leaking valve or seal could cost anywhere from $50 to $1,000. A broken fuel injector or pump could run as high as $2,000. What’s most serious is a blown head gasket or a cracked cylinder, which isn’t just costly, but also difficult to repair. Depending on what kind of car you drive, you could spend up to $2,500 to repair these problems.

Whenever you see white smoke coming from the engine, you are going to want to have the problem fixed. Otherwise, you are going to end up with extensive damage to the engine that will require a complete replacement.

Why Is My Car Smoking?

https://mechanicbase.com/engine/white-smoke-coming-from-the-engine-causes-fixes/