10 Causes of White Smoke from Exhaust When Accelerating + Fixing!

Automobiles have intricate design and complex working, and they are prone to wear and tear easily. One common issue can be smoke coming out of the exhaust. Smoke can be of different colors and caused by various underlying issues. These issues can be severe or trivial, or they could also mean nothing. It entirely depends on the smoke color and its thickness. Usually, white smoke from exhaust when accelerating is common during winters.

When accelerating, white smoke from exhaust can be an issue if it continues to smoke and is thick. In such cases, you should get your car checked as it can be because of some severe problem.

“If the smoke is not thick and is disappearing within a few seconds, then it may mean nothing because it is common and usually happens as a result of condensation.”

Now, there are manifold reasons or causes of white smoke from exhaust. It does not matter if the issue is big or small; you should know what causes white smoke as an owner of the vehicle.

What is White Smoke?

Before you learn the issues that cause white smoke from the exhaust, let us first understand what does white smoke from exhaust mean? Whenever you see white smoke from exhaust, it can indicate a severe problem in your automobile. White smoke can be a result of normal condensation. When condensation builds up in the exhaust system, it can cause white steam that is thin like vapor. You should not panic in such a case, as the smoke will disappear quickly.

On the other hand, if the thickness of smoke is more, and it lingers long, this can be an issue because of a coolant leak. It can further lead to numerous problems, such as a blown head gasket, cracked engine block, or damaged cylinder head. You might have to incur heavy expenses to resolve such issues. Hence, it would be better to give immediate attention to such problems before they exacerbate.

10 Causes of white smoke from exhaust

As a driver or owner of the car, whenever you see white smoke from exhaust when accelerating, your car might be indicating some problem. Hence, it is vital that you should know what these indications mean and what the causes of white smoke from exhaust are. Below-mentioned is some of the common issues that cause white smoke:

1.      Coolant Leak

Coolant is another vital thing required for the smooth working of the engine.

“A car coolant is also called antifreeze; it prevents the car engine from overheating.”

The parts that come in contact with the coolant are also lubricated, thereby protecting the water pump, cylinder, piston timing, head gasket, etc., from any damage. When this coolant leaks, it mixes with the fuel mixture and starts to burn, which can cause white smoke from exhaust.

Also, when coolant leaks, the quantity of coolant is reduced, which can cause the car to heat up and emit white smoke from exhaust when accelerating. Thus, if you face such a situation, fix the issues because it can cause severe consequences due to overheating.

2.      Condensation

This is one of the common causes of white smoke from exhaust pipes. Especially in winters, you might notice white smoke from your car’s exhaust. This is because the condensation gets accumulated in the exhaust pipe, and when these hot exhaust gases come in contact with the cold atmosphere, thin vapor like steam is the result. This smoke would take a few seconds or a minute to disappear and usually nothing to worry about. However, it is thick and lasts longer, then you might have a problem and should get it checked.

3.      Oil Leak

When there is excessive oil in the combustion chamber, it results in white smoke. The engine requires a specific amount of fuel and air to work efficiently, and this fuel mixture should not be too rich or unbalanced. If the amount of air is more or fuel is more, it would cause a problem. Therefore, when oil leaks in the chamber, the engine will burn more fuel, and this causes white smoke from exhaust when accelerating.

4.      Cracked Engine Block

An engine block is made up of aluminum alloy or iron used to support other components of the engine. The engine block transfers the heat built from the friction to the engine coolant and the atmosphere. A crack in the engine block can cause coolant to leak, resulting in white smoke.

Even a small crack can cause issues allowing the coolant to mix with the oil. When the coolant burns, it causes white smoke from exhaust when accelerating. So, if you see such smoke, you should get it repaired or fixed immediately.

5.      Cracked Cylinder Head

The cylinder heads control the airflow that flows in and out of the cylinder. Also, the amount of fuel deployed is governed by the cylinder head. When there is a crack in the cylinder head, it is caused by overheating, head gasket failure, lack of coolant flow, or coolant leak.

If the crack in the engine is too extreme, it can lead to drastic consequences such as terminal damage to the engine. Since coolant passages run along with the cylinder head, when there is a crack, the coolant can enter the combustion chamber and burn along with fuel. Because of this, white smoke is emitted from the exhaust pipe.

6.      Blown Head Gasket

A head gasket is a part that is fixed between the cylinder head and engine block. It functions as a seal between these two and prevents pressure loss and engine fluid leaks. It keeps a check on cylinders, pistons, and oil return passages. However, if the head gasket is blown, the pressure is lost as there is no medium to regulate it. Susequently, your car will lose its power.

Also, a blown head gasket can cause coolant to leak, resulting in white smoke from exhaust when accelerating. The Head gasket is blown usually when the car is frequently overheated or if you continue to drive with an overheated engine. Therefore, you must ensure that the car’s cooling system works efficiently and is in good condition.

7.      Bad Fuel Injector

A fuel injector is used to inject fuel into the engine. As the engine needs the correct air-fuel mixture for completing the combustion process, this device helps it achieve efficient combustion. It is an electronically controlled device. Besides, timing, amount, and pressure of fuel, etc., are controlled by ECU (electronic control unit).

If your fuel injector is bad, then it can cause a misfire. It will disrupt the required balance of air and fuel entering the engine. Since the amount of fuel required in the engine is more than it should be, it needs to be burned and expelled. This can cause white smoke from the exhaust.

8.      Error in Electronic Control Unit (ECU)

Electronic Control Unit (ECU) is an electronic device installed in the vehicle.

“It is a microcontroller and has embedded software that controls the working of ECU.”

Further, ECU determined and governed multiple electronic systems in the vehicle. It can be costly if your ECU gets damaged (around $1000-$3000).

The ECU is responsible for the correct functioning of the fuel injector. How much fuel to inject, at what time it should inject, and what pressure should be applied are some of the functions that the ECU governs. If there is a glitch in ECU, it can cause the fuel injector to inject fuel at the wrong time or inject excessive fuel. As a result, it can cause white smoke from exhaust when accelerating.

9.      Piston Rings Leak

Pistons rings support the movement of pistons. Pistons move up and down, so it is the job of rings to support them and aid in their smooth and efficient movement. If the piston rings lose their grip or get worn, they cause an oil leak. When this oil gets into the combustion chamber, it can lead to white smoke from exhaust pipe.

Bad piston rings or leaks in piston rings can also cause misfiring, which further causes white smoke from exhaust. If you notice such an issue, it means the piston rings are no longer capable of sealing the cylinder. Hence, you should have this issue fixed on time.

10.  Valve Seal Leak

Like the piston rings, the valve seal also controls the oil consumption. Other than this, it also maintains valve lubrication. Engine power loss, popping noise, high smoke, etc., are indications of bad valve sets. Like piston ring leaks, if the valve seal leaks, it causes the oil to enter the combustion chamber. If the leak is too much, the oil drip on the hot engine and exhaust manifold, causing smoke. Also, when the engine burns excessive oil, it can result in white smoke from exhaust when accelerating.

How to Fix White Smoke from Exhaust

If you see white smoke from exhaust when accelerating, it could be an issue because of coolant leakage. Follow the following steps to fix this issue:

Step 1: Smell the smoke

The first thing you should check is the smell of the smoke. If it is a coolant leak, the smoke is likely to have a sweet smell. If you smell steam or water, then it could be normal condensation. However, if the smell is toxic, it could mean a damaged catalytic converter. So, if the smell is not sweet or just steam, then seek professional help.

Step 2: Inspect Intake Gasket

You need to check the intake gasket and see if it is damaged. A damaged intake gasket can cause coolant to enter the combustion chamber. When the coolant burns in the chamber it causes white smoke from exhaust when accelerating. If it is damaged, remove the intake manifold and check the intake gasket. If damaged or rusted, repair it; otherwise, replace it.

Step 3: Inspect Head Gasket

You should check the head gasket only if the intake gasket is working perfectly. Again, a leak in the head gasket can cause coolant to get into the combustion chamber, causing white smoke. If it is damaged, then replace or repair the head gasket.

Step 4: Check if there is any crack in the Cylinder Head

If both your intake gasket and head gasket are working fine, you should check if there is any crack in the cylinder head. Since the cylinder head is made of aluminum, it can be cracked due to overheating. If there is a crack, you have to replace it. There is no other option left in front of you.

Other Color Smoke Emitted by Exhaust

Just like white smoke from exhaust indicates various issues, similarly, there are other colors smokes as well that show or signify other issues. Some common smoke colors are:

Black Exhaust Smoke

As stated earlier, an engine requires a correct ratio of air and fuel mixture, and if this mixture is too rich, it can cause black smoke from exhaust. It can be because of a blocked manifold, intake valves are unable to pass the proper air pressure, or fuel injectors are injecting too little or too much fuel.

Another reason for this could be a clogged air filter, you do not need to fret as a clogged filter would not impact your gas mileage, but it would affect the vehicle’s performance. So, if you see black smoke from the exhaust, you should get it checked by a technician as it is not normal.

Gray Exhaust Smoke

Gray exhaust smoke could also mean an issue with the car. Gray smoke from the exhaust is not regular, and hence, if you notice gray smoke from exhaust, seek professional help.

Smoke can be grey because of damaged piston rings, worn cylinder walls, or leakage in valve seals. Also, a blown head gasket can be a reason behind gray smoke. The engine might be working extensively, or a coolant leak can also be a reason behind gray smoke from the exhaust.

Blue Exhaust Smoke

Some people categorize the blue and grey smoke together. It also happens that at first, often, blue smoke looks like gray smoke. It would help if you were observant and patient to distinguish the bluish tint in the smoke.

“Blue smoke is an indicator that your car’s engine is burning lots of oil.”

Again blue smoke from exhaust is not normal, and it can be a bad sign and needs immediate attention. It can be either because of damage to internal components of the engine or issues with the oil. An oil leak is again a common cause of blue smoke. This leak can further be caused due to various problems such as damage in piston rings, valve seal leaks, etc.

Overfilling of oil can also cause blue smoke. Overfilling can cause oil to churn, whip and this can cause smoke which will cause problems like not lubricating properly and causing other similar damages. Thus, ensure to provide immediate attention.

Frequently Asked Questions (FAQs)

Can white smoke be caused by dirty oil?

There should be a proper mixture of air and fuel; there should not be anything else. If due to any reason, the oil enters this chamber, then it can mix with this mixture and cause white smoke. This white smoke will be thick and will exit from the exhaust pipe. You should take professional help to figure out and fix the issue as ignoring or preventing the repair can worsen the issue.

Can bad spark plugs cause white smoke?

No, “bad spark plugs do not cause white smoke.”

If the spark plugs are not working well, the engine will run roughly, and the unburned fuel will cause black smoke rather than white or grey. A coolant leak causes white smoke because of a crack in the cylinder head, engine block, or blown head gasket.

How much white smoke from exhaust is normal?

A thin vapor more like steam instead of smoke is normal. This can result from condensation that gets collected in the exhaust pipe. It is common during winters because exhaust gases are hot, and when these gases mix with the cold environment, they cause vapor-like smoke. This smoke is thin and dissipates within a minute or just a few seconds. If this is the case, then it is normal.


The smooth functioning of the engine and its components is essential. If you notice any sign that can hint at an issue, it is better to check it, just like white smoke from exhaust when accelerating means a coolant leak. Similarly, steam or vapor from exhaust can be because of condensation. Therefore, it is crucial to keep checking and aware of small signs to prevent significant issues.

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