Is It Bad If Your Oil Smells Like Gas? [See 9 Reasons]

Whenever your oil starts smelling like gas, you probably have a gas-oil mixture. As you may know, gas and oil are primary fluids found in a vehicle that makes sure that your car runs smoothly. So, whenever you perceive oil smells like gas, then you shouldn’t take it lightly.

As a car owner, you must understand the causes of your motor oil smelling like gas to enable you to solve these problems and prevent them from happening in the future.

There are causes of a gas-oil mixture in a car, which could be as a result of driving short distances always or due to bad engine components.

This article explains in detail what causes your oil to smell like gas and how you can fix the problem of your engine oil smelling like gas.

9 Reasons Why Oil Smells Like Gas

1. Very Rich Air-Fuel Mixture

For every car engine, there’s a specific ratio of air to fuel. When the fuel that enters the cylinder becomes greater than needed, the combustion chambers won’t be able to ignite all the fuel, and this means that excessive fuel will flow to the oil pan resulting to a very rich air-fuel mixture.

However, there are a handful of reasons for fuel mixture to become very rich. These include issues in the oxygen sensor, mass airflow sensor problems, and damaged MAP sensors.

One of the primary reasons responsible for your gas getting into your engine oil is that your gas mixture is too rich. Whenever your fuel mixture becomes very rich, your vehicle’s combustion chamber will not ignite all of the fuel, which will make the fuel run via the piston rings down into the oil pan.

However, there might be other sensors or issues making the fuel mixture get too rich. It is recommended that you read the trouble codes using an OBD2 scanner to check if any stored trouble codes will show you where the problem may be coming from before troubleshooting.

2. Issues with the Combustion Chamber

Whenever your oil smells like gas, it means that your combustion chamber isn’t igniting very well. Car engine knocking or other problems which are caused by engine pressure or heat not being correctly inspected can make fuel leak into your oil pan causing it to smell.

Should you notice any strange engine performance such as occasional pinging sound, and oil smell like gas, it means there are issues with your combustion chamber.

oil smells like gas

3. Misfires

Remember that misfire sometimes happens whenever air-fuel mixture isn’t receiving ignition as it is supposed to, and the combustion cycle is disturbed. Due to the inability of the air-fuel mixture to get ignited, your vehicle’s gas can wash off your cylinder walls, and cause the compression to be lowered, and then flow through the piston rings. When this happens, it can cause the gas to pour down via the piston rings and fill your oil pan with fuel.

4. Spark Plugs

Note that misfires are most commonly caused by when you have a faulty spark plug, which can also cause combustion chamber problems. However, this may also be technically a combustion chamber problem, but it’s very common, and it can be inspected and repaired easily.

5. Not Having Oil Change

First, you should know that not changing your engine oil won’t directly make the oil smell like gas. This is because any small amount of gas that enters your engine oil won’t impact, or won’t be noticeable. But whenever this small amount of gas passes and builds up in your crankcase and no change of oil is done, then you will begin to observe the oil smells like gas once the fuel passes 2.5% of the oil quantity.

6. A Damaged or Worn Piston Rings

In case you don’t know, your car’s piston rings serve lots of purposes. However, one of its functions is to regulate the oil pressure and application in your car. This means that whenever they’re worn down or damaged in whatever way, it may cause fuel to get into your oil pan making your oil smells like gas which you’ve noticed. In case you notice your vehicle is giving off too much exhaust smoke, and the oil smells like gas, it signals you have a bad piston ring.

7. A Stuck Fuel Injector

Your vehicle fuel injectors are made to close themselves automatically once the right amount of fuel is sent to the combustion chamber. So, whenever the fuel injectors become very bad, they might open and pour excessive fuel into the cylinder walls. Anytime this happens, you’ll observe oil smells like gas. Once the gas in the crankcase becomes too much, this can cause a lot of damages to your engine.

8. Dirty Fuel

In some cases, you might end up buying dirty fuel from a fuel station. Most times, the dirt can come from the truck that supplied the fuel, or due to badly refined petroleum. Once you pour such fuel into your car, it might not burn due to the dirt in the gas. As you may or may not know, any unburnt gas will find its way to the crankcase. This may lead to your oil smelling like gas.

9. Always Driving Short Distances

Usually, in some car engines, the gas would run down more or less into the oil pan. And when the oil temperature gets high, the gas will come out as vapor from the engine oil.

This means that if you only drive for short distances, your car engine oil will not reach its high temperature that’s enough to vaporize the gasoline, and this will cause your oil pan to be filled up with gas.

However, you can also replace your engine oil and filter. I advise that you change your engine oil at shorter intervals if you know that you usually drive for shorter distances.

Final Answer! Is It Bad If Your Oil Smells like Gas?

Absolutely. Your oil smelling like gas simply means that there’s a likelihood of something going bad with your engine.

Even if you think there are no issues, you should be able to inspect your engine properly.

Get your mechanic to help with a thorough inspection.

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How to Fix Oil Smelling Like Gas

Should you notice your engine oil smells like gas, it is most likely you have an oil-gas mixture. Once the gas remains in the crankcase for too long, it will affect the oil lubricating power and make it less viscous. This could cause your engine’s internal components to wear out quickly.

Your vehicle’s engine oil formulation can provide adequate protection up to a certain level when it is diluted. So, one of the things that are needed to be done to manage oil dilution is to regularly go for a long drive. You can choose to do a couple of hours on the highway to raise the car to optimum operating temperature. This can help dry the fuel in the crankcase.

Another way you can fix this is to change the engine oil frequently if you usually drive short distances.


If you drive your vehicle every day, and you don’t want to damage your engine, then your engine oil should be inspected and changed regularly.

You should always remember that many car manufacturers recommend that car owners change their motor oil regularly in harsh operating environments.

Consult your mechanic whenever you notice that the oil level has climbed far above the standard gauge.

Once you notice that your oil smells like gas, don’t panic. It doesn’t mean that you’re about to have an engine failure. It simply means that there’s something that needs to be taken seriously, especially if the smell persists.

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