White Smoke From Exhaust Smells Like Gas [Solved]

Dealing with exhaust smoke is not unusual for a car owner. But most car owners fail to measure the severity of this problem based on different types of smoke. 

For example, white smoke from the exhaust like gas is produced when your car is on the way. Also, the white smoke will come out of the exhaust system when it’s cold outside or idling the car. 

It doesn’t matter how or what causes the white smoke from the exhaust smells like gas. What matters most is- you should deal with the white exhaust smoke before turning this into a big issue. 

white smoke from exhaust smells like gas

And this guide will help you understand the meaning of the white smoke, what causes this issue, and how you solve it. So, let’s get started right here. 

White Smoke From Exhaust Smells Like Gas [Solved]

A blown head gasket, a fuel leak, and coolant leak are some culprits that cause the white smoke to come out of exhaust. The white exhaust smoke due to these reasons will smell like nasty gas or burning oil. 

Therefore, adding excessive oil, leaking transmission fluid, and a bad catalytic converter are some reasons behind the white smoke from the exhaust. 

Below, we will break down each of them. So, keep scrolling. 

Note: You can also read how to fix Coolant Leak front passenger side tire

01. Condensation

White smoke from exhaust doesn’t always indicate a problem. It’s simply condensation. Generally, white smoke is water steam, or vapor. 

If you notice the white & wispy smoke at startup, especially on colder days, and it disappears within 30 seconds, understand it’s just condensation. In other words, it’s normal. 

We recommend you run a diagnostics and compression test to verify. 

02. A Blown Head Gasket

A cracked or blown head gasket is the most common reason behind white exhaust smoke. When the head gasket gets damaged, it will introduce the coolant into the combustion chamber. In simple words, the blown-out head gasket leaks coolant into the combustion chamber. 

But the heck is- coolant doesn’t burn up like fuel because it’s not part of the combustion process but it will vaporize. Consequently, it will produce a lot of white smoke from the exhaust. 

Apart from white smoke, the blown-out head gasket also causes the combustion chamber extremely clean but makes the cooling system dirty. In short, white smoke, a clean combustion chamber, and a dirty cooling system are the signs of a damaged head gasket. 

If you notice all these symptoms at once, be ready to spend a fortune because it requires a mechanic to disassemble a lot of parts to replace the head gasket

03. Adding Too Much Oil

You must top up the engine with oil to keep every moving part of the engine lubricated. But adding too much fuel brings no good to your vehicle’s engine. It causes white exhaust smoke. 

Keep in mind, oil is not the problem here. What creates the problem is when the oil goes into the combustion chamber. 

When you add too much oil, the oil leaks out of the piston rings and makes its way into the combustion chamber. Then, it mixes with the air & fuel and gets burnt. Consequently, it produces dense white smoke.

04. A Fuel Leak

A fuel leak can also cause the exhaust to emit white smoke. Usually, an oil leak will happen when the piston rings get cracked. A faulty or damaged valve seal causes the oil to leak into the combustion chamber, blend with the fuel and burn the oil. 

If it happens, you can see white or bluish smoke from the exhaust pipe. We suggest you deal with this fuel leak issue right off the bat. Otherwise, it will lead to further engine damage. 

05. Low Coolant Or Coolant Is Leaking

A leaking coolant or low coolant level can also produce white smoke. Usually, a crack in the cylinder head or engine block causes the coolant to leak out and go into the combustion chamber. 

When the coolant mixes with the engine oil, it turns into a milkshake appearance. The notable sign of a coolant leak is- the white smoke will come out of the exhaust pipe and leave a sweet smell in the air. 

Because of the low coolant level, the engine will get overheated and cause the head gasket to fail. As a result, the engine will begin to wear out quickly. To avoid this damage, bring your car to a professional to fix the coolant leak. 

06. Transmission Fluid Is Leaking

White smoke from the exhaust when accelerating! If you notice this problem, we bet the problem is with the transmission fluid. In this case, your exhaust can smell like burning oil or nasty gas.  

The transmission fluid will leak due to a worn-out transmission pan, a damaged gasket, or cracked fluid lines. When this fluid will leak, it can burn and generate white smoke from the exhaust. 

07. A Bad Catalytic Converter

A bad catalytic converter can also be the culprit behind the white smoke issue. If white smoke is coming out of the exhaust and the dashboard displays DTCs related to catalytic converters, it’s because of burning oil. 

The oil leaks into the combustion chamber due to a worn-out piston ring. This faulty piston ring will also end up getting oil into the catalytic converter. As a result, the oil will burn in the combustion chamber and exhaust the white smoke through the exhaust system. 

We recommend you hire a certified mechanic to deal with the catalytic converter issue and the white exhaust smoke problem. 

Apart from these, you may also encounter the following white smoke problems.

White Smoke From Exhaust On Startup Then Goes Away

If you observe white smoke coming out of the exhaust system but going away within a few seconds, there is nothing to worry about. It’s simply condensation. 

When the hot gasses meet the outside cold air, it will create condensation & steam. This white smoke will disappear once your engine reaches its operating temperature. 

In short, you don’t need to do anything if the white smoke comes out of the exhaust on startup and disappears. However, you can run a compression test if it creates confusion. 

White Smoke From Exhaust After Sitting Idle A Few Minutes

A defective head gasket is the culprit behind this issue. The white smoke from the exhaust will come when you startup the engine after it has been sitting for a while. 

When the engine is running, the combustion chamber is developing about 150 kPa of combustion pressure while your cooling system is only producing about 16 PSI of vapor pressure.

The high combustion chamber pushes the radiator water away from the breach and pressurizes the cooling system. This prevents any coolant from entering the combustion chamber, which stops the vehicle from smoking.

However, when you turn the engine off, the combustion chamber is no longer producing pressure but the cooling system is still pressurized. The radiator water will dribble unimpeded through the head gasket breach and into the combustion chamber. 

But when you restart the engine, the water and glycol in the combustion chamber turn into steam and white smoke again. This level of white smoke indicates that there is a small hole in the head gasket. 

You can easily fix this by pouring the Liquid Intelligence 245. 


Why does my exhaust smoke smell like gas?

Your exhaust smoke smells like gas if too much oil or too much air goes into the combustion chamber. A leaking head gasket causes the oil to go into the combustion chamber and burn the oil. As a result, your exhaust smoke smells like gas or nasty burning plastic. 

Is it safe to drive with white smoke from exhaust?

No, it’s not safe to drive your car with white smoke from exhaust as it indicates the head gasket is leaking or the coolant leaks into the combustion chamber. If you drive your car with this issue, it will bring severe damage to the engine. 

How do I stop white smoke coming from my exhaust?

You can easily stop white smoke coming from the exhaust by finding the source of this issue. Generally, a leaking head gasket, coolant leak, and too much oil can cause the exhaust to emit white smoke. Just fix these issues and the exhaust system will stop producing white smoke. 


White smoke from exhaust smells like gas generally indicates there is an issue with the head gasket. So, inspect the head gasket to see whether it gets damaged or not. If it gets cracked, you should fix it immediately. Otherwise, oil or coolant will leak into the combustion chamber and produce white smoke. If you fail to solve this issue, stop the engine and call a mechanic to fix this problem for you. 

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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