Why Does Oil Smell Like Gas?

April 23, 2022

Mechanic found that the engine oil was mixed with the gas and smell like gas fuel.

Your car’s oil should not smell like gas, and if it does, you should check the reason. It might be because you don’t drive your vehicle long distance; hence, its engine doesn’t really get hot. It might also be a case of a rich air-fuel mixture due to faulty injectors or misfires. Of course, you don’t need to visit your favorite mechanic if you can figure out why your oil smells like gas.

Your car, it is said, is the extension of your personality, and thus, you should know what is happening with your car. Besides, it should alarm you if you notice something unusual or off in the functioning and components of your car. If your car’s oil, for example, smells like gas, it should prod you to determine the reason why the oil is smelling like gas.

Possible Causes of Oil Smelling Like Gas

The abovementioned possible reasons why oil smells like gas are not the only reasons that cause such a gas-like smell in the oil. It could be any of the following reasons, and if you want to narrow down the reasons, it will help to know these following reasons:

Rich Air-fuel Mixture

Gas can mix with your oil if your fuel mixture appears to be too rich. Since it is too rich, the combustion chamber might fail to ignite the fuel completely. The excess fuel will then flow down to the piston rings and the oil pan. However, troubleshooting why the fuel mixture becomes too rich isn’t easy because other problems or sensors might be causing this issue.

You Only Engage in Short Distance Drive!

On many car engines, gas will more often reach the oil pan. If the oil temperature, for example, gets too high, gas will get vaporized and mix with the engine oil. Nevertheless, if you don’t drive long distances, you don’t give your engine oil enough chance to reach a high temperature for vaporizing gasoline. 

Hence, you end up with an oil pan filled with gas for a while. In such a case, you should replace the filter and engine oil. Moreover, if you don’t drive long distances, it will be best to shorten the intervals between every engine oil change.

Bad Piston Rings

Another factor contributing to your car’s oil smelling like gas is when the piston rings are malfunctioning or bad. More fuel might reach the combustion chamber down to the oil pan in such a case. Yet, this problem doesn’t happen more often, and if it happens, it will be challenging to repair because you need to dismount the entire engine apart. 

So, before you assume that it might be due to bad piston rings, you can first check the possibility of the other causes. One way to determine if the reason behind the gas-smelling oil is the piston rings is to engage in a leak-down or compression test.

Faulty Settings or Carburetor

If you have an old car, it might be a case of a faulty carburetor. Cars with carburetors feature a different fuel mechanism that the diaphragm handles, controlled mainly by the gas pedal. Such a mechanism is entirely mechanical, and the airflow controller can get stuck. 

If that happens, the fuel flows in according to the ratio of the mixture. Moreover, it allows the gas into the oil, which might become an issue. The excess gas will flow down onto the oil pan and get mixed with the oil.

Irregular and Infrequent Oil Changes

A minimal amount of fuel usually gets into the engine’s lubricating oil, even if there is no mechanical issue. This minimal amount of gas doesn’t pose any real risk to the engine’s functioning. 

Yet, this might cause problems over time, and in the absence of regular oil changes, this fuel might combine with other elements and turn into other compounds. This will result in fuel dilution that brings in a gasoline-like smell.


If you’re familiar with the modern vehicle’s engines, you will notice that they are primarily fuel-injected ones. There are tiny injection devices in fuel-injected vehicles, and these devices deliver fuel into the engine as needed. 

Solenoid operates these injectors, and a computer controls these devices. Thus, the engine only gets the right fuel amount inside the cylinders. Solenoids, of course, are mechanical, and they are susceptible to malfunctioning. There will be instances when the solenoid would get stuck and remains open. 

In such a case, gasoline can get inside, being watery. This fuel mixes with oil. Some of it will get to the oil pan and combine with oil while your car runs if there is an excessive gas flow. Thus, your oil winds up with a gasoline-like.  

Combustion Chamber Issues

Oil smelling like gas can also be a combustion chamber issue. It might be that the combustion chamber doesn’t ignite correctly. If the combustion chamber exhibits knocking or fails to regulate pressure or heat, it might cause gas to leak onto the oil pan, which, in turn, might cause gas odor in your oil. 

Once you notice some changes or irregularities in your engine’s functioning and if you sometimes hear a pinging sound in your engine or smell gas, your combustion chamber might be problematic or have some issues.

Frequently Asked Questions

Aside from knowing the potential sources of why your oil smells like gas, it will also help if you familiarize yourself with the FAQs about gasoline-smelling oil:

Can You See the Gas in Oil?

You might not see the gas in oil, especially when they mix with each other. Yet, you might notice a thinning of oil, which might indicate a contamination. You’ll see that the motor oil seems more translucent than it should be. Moreover, if you touch the gasoline-contaminated oil, you will notice that it feels somewhat thin. 

You’ll see this if you rub the oil between your fingers. This delicate feeling is indicative of viscosity loss, and this loss of viscosity might speed up the wearing of bearing.

Does Gas Frequently Mix With Oil?

You might not notice the mixing of oil and gas because this might happen at a microscopic level and in tiny quantities. Of course, a system—the PCV System—deals with this issue. If the mixing of gas and oil is only in small amounts, you don’t need to worry about it. In fact, it is but natural to happen. On the other hand, most engines should burn oil while driving. 

The mixing of oil and gas might result in the oil turning into sludge. The effect of this sludge is similar to how a plaque can block the arteries. As such, it can cause corrosion and engine shut down. 

If you want to avoid this issue, you might as well go for a motor oil that is sludge resistant. Yet, you won’t find an oil that is entirely sludge resistant. So, you should take other steps to prevent sludge formation.

Can I Still Drive Safely If I Smell Gas in My Car’s Engine Oil?

Experts will tell you not to drive your car if you smell gas in the engine oil. The reason is that you risk the integrity of your engine for gas would thin oil, reducing the viscosity of the oil. This issue will lead to premature wearing of essential components of your engine. 

Nevertheless, it is also wrong to surmise that driving with contaminated oil will quickly translate to engine failure. Yet, over time, it will cause harm to your engine. Hence, it is advisable not to drive in such a case. 

But if you need to drive the car, you should consider some precautions. First, you need to replace the oil filter and change the oil. In this way, you can take oil samples for analysis by experts. Thus, you will know if you got a diluted oil. If the oil dilution gets promptly addressed, you can prevent secondary issues.

Should I Worry If the Oil Smells Like Gas?

When your oil smells like gas, it is indicative that there’s something wrong with your engine. So, it necessitates checking your engine to know where this issue originates. Yet, if you want to know why there is gas in the oil, you can surmise it into two reasons. 

First, it might be a case of a leaking fuel into the oil. The gas has been heated, vaporizing it instead of burning it. This means that your car is not maximizing the use of the gas you are buying. How much is going to the drain depends on how much is leaking onto the oil. 

Second, it might cause the changing of oil composition. If the change in oil composition is drastic and the oil is thinning out fast, it will not lubricate the engine well, leading to faster wear and tear. Of course, the breakdown of your engine will not be immediate. But if you don’t address the issue promptly, it could lead to more expensive repairs and replacements.


If you’ve been driving your car for a few years and suddenly notice a gas-like smell in your oil, you don’t need to panic. You need to diagnose and see if other symptoms accompany the gas-like smell. You can check out the abovementioned possible causes to narrow down the possible causes to the probable causes.

Of course, if you don’t know how to troubleshoot your car’s problem, you should not think twice about sending your car to a professional mechanic to determine the real cause of the problem. However, your knowledge about the possible causes of this issue will prove invaluable if you want to troubleshoot the problem independently.