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6 Reasons Oil Smells Like Gas

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Of all the fluids that ensure that your car runs smoothly, gas and oil are at the very top of the list. In normal conditions, both of these fluids work in tandem but don’t mix. So when your oil smells like gas, you have every reason to worry.

The main reasons oil smells like gas in your vehicle have to do with faulty injectors or problems with the ignition system. You could also have an unbalanced air-fuel ratio, internal engine wear, or you tend to change your oil infrequently. If you only take your vehicle on short trips all the time, you could have this problem as well.

What causes this problem, gas-tainted oil in the vehicle is a serious issue that requires immediate looking into to fix the problem. Read more to find out what causes oil to smell like gas and what you can do about it. 

Is it Bad if Your Oil Smells Like Gas?

Is it Bad if Your Oil Smells Like Gas

When gas leaks into the crankcase in increasing amounts or stays there, you might not notice at first. But soon, the signs that the oil is tainted with gas will crop up. Since oil is more viscous than gas, the oil will lose its ability to lubricate the internal engine parts and reduce heating. This can lead to engine overheating and accelerate wear and tear.

Another consequence of gas leaking into the oil pan is that you need to refuel more frequently than you are used to. The leaking gas goes to waste which turns the vehicle into a gas guzzler.

Signs of Gas-Oil Mixture

The symptoms you have a gas-oil mixture problem might be hard to detect at first. But eventually, you might notice a smell of gas coming out of the engine while driving. The exhaust fumes would turn white. And when you check the oil levels, the dipstick would come out smelling of gasoline.

Moreover, when you check the oil in the engine, you’ll notice that oil levels are rising instead of dipping. Normally, oil levels are reduced the more you drive the vehicle. Increased oil would indicate that some fluid, either gas or water, is seeping into the oil pan. Smell the dipstick to tell if the oil is tainted with gas.

What Causes Oil to Smell Like Gas?

What Causes Oil to Smell Like Gas

To avoid having to spend more money on gas and the potential damage to the engine, you need to figure out what causes gas to leak into the oil pan. In general, there are 6 possible reasons.

  1. Faulty Fuel Injectors

When oil smells like gas in your engine, the first place to look is the fuel injectors. They are responsible for sending a fixed amount of gas-air mixture to the walls of the cylinder. When the fuel injectors are damaged for one reason or another, they will spray the inside of the cylinder with too much fuel which ends up in the crankcase and gets mixed with the oil.

  1. Damaged Piston Rings

The one job of piston rings is to prevent the fluids in the engine, mainly gas and oil, from leaking and getting mixed. With wear and tear, the gas infiltrates the oil pan through the damaged piston rings and mixes with the oil. You should also check the piston rings in the crankcase. If they’re worn out, oil could be getting into the combustion chamber as well.

  1. Rich Fuel

The combustion chamber gets a mixture of fuel and air at a specific ratio. If the mixture has more fuel than air, then some of the gas will not get burned. That raw fuel will leak into the crankcase and get mixed with the oil. The cause of the rich fuel problem is either a faulty carburetor or damaged fuel injectors.

  1. Infrequent Oil Change

Even if you have no wear and tear in the engine and all the internal parts are in good shape, gas could leak into the oil pan in trace amounts. If you don’t change your oil, there will be a gas build-up. Once that build-up reaches 2.5 percent of the oil volume in the crankcase, it eventually becomes noticeable and starts to cause problems.

  1. Short Trips

Although the oil pan can have gas leaks sometimes, when you drive, the oil pan gets heated up which causes the gas to evaporate and leak back out of the crankcase. But it takes a long drive for the engine to heat up enough for the gas in the oil pan to turn into fumes. If you only drive for short distances inside your city the gas will not vaporize and cause a build-up in the oil pan.

  1.  Dirty Fuel

Not all of the fuel you fill the tank with is of top quality. Some fuel is contaminated with dirt due to poor storage in the gas station tanks or because the vehicle that fueled before had dirt in the tank that passes on to the nozzle. Either way, with dirt in the combustion chamber some of the fuel will not burn and leak into the oil pan. 

Besides damaging the internal components of the engine, dirty fuel will cost you money in the long run. It’s less economical which means the car will get less mileage per gallon and will have to refuel the car more often.

Will Gas Evaporate out of Oil?

Will Gas Evaporate out of Oil

Although gas tends to vaporize if it leaks into the crankcase, that’s only true if the crankcase is hot enough during a long drive. The leaking gas has to be in small amounts and it should evaporate on the hot walls of the oil pans before it reaches the oil. If the gas mixes with the oil, it’s hard for it to evaporate since gas dissolves in oil.  

How Do You Fix Oil That Smells Like Gas?

How do you Fix Oil that Smells like Gas

With all the damage that an oil-gas mixture can cause to the internal components of the engine, you need to fix the problem as soon as you get a whiff of raw gasoline while driving or notice the vehicle exhaust turning white. Here’s how to fix this problem.

  • Long Drives: Try to take the car for long drives more often if your trips are limited to short distances inside of your city. This will allow the oil pan to heat up long enough to vaporize the leaking gas and prevent oil dilution.
  • Replace Damaged Components: Check that the piston rings are not damaged. If they are, replace them with new ones to stop the oil and gas leaks.
  • Change your Oil: The recommended oil change intervals are every 5,000 to 7,500 miles. If you ignore these standards, you risk having oil dilution and gas build-up that would accelerate the wear and tear of the engine.
  • Regular Maintenance: Not all causes of gas leaking into oil are easy to detect. Some internal damage to the carburetor or fuel injectors needs an accurate diagnosis and replacement by a technician. Only a professional can tell you if the combustion chamber is getting an unbalanced fuel-air ratio or not.


Oil dilution is a serious problem with many vehicles. When the gas leaks into the crankcase and contaminates the oil, this can increase the wear and tear of the internal components of the engine. As the oil becomes thinner and less viscous, it loses its lubricating properties which leads to the engine heating up.

Take the vehicle on long drives more often to prevent gas build-up in the oil pan and check that the piston rings are not damaged. You should also change the oil in the vehicle more often and maintain the car regularly.

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