I Accidentally Put The Wrong Gas In My Car, What Next?

I Accidentally Put The Wrong Gas In My Car

You are not alone. It is a common mistake to hear someone saying “I accidentally put the wrong gas in my car”. Find out what you need to do for accidentally putting premium, regular, E85, diesel, 89, or 91 fuel types in your car.

Depending with the fuel, adding the wrong fuel to a wrong car can have minimal to no impact, moderate impact, or be catastrophic as soon as you start your car engine. Be sure to know the potential consequences of your actions before igniting your vehicle engine.

Putting wrong gas can imply putting premium in a regular car, diesel in gas car, gas in E85, or vice versa just to name a few examples. However, as long as you have topped up your fuel tank with the wrong fuel that is not recommended by the vehicle manufacture something is likely to happen.

What Happens When You Put Wrong Fuel In Your Car

Accidentally Put E85 Instead of Gas

Fuel named E85 has higher content of ethanol. Consequently, if your vehicle is flex-fuel then adding E85 to a gas car has no significant impact. Flex fuel means ability to switch between fuel types.

However, if your vehicle is has not been recommended as flex fuel by manufacturer, mixing E85 to gas vehicle will negatively affect the engine performance.

Immediately you notice that you have mixed E85 to a gas vehicle, stop adding more as soon as possible. Top up with the recommended regular gas and you will be fine. Mixing E85 to gas once in a while shouldn’t cause significant impact, but you shouldn’t.

Accidentally Put Diesel Instead of Gas

As soon as you realize you have topped up diesel into you gas vehicle, you have to park safely and stop the vehicle if you were moving. It is because diesel fuel will damage your gas engine.

A gas engine has no capacity to burn the diesel and if you continue to drive it will stop a few distance once the gas that was there is depleted and diesel is in circulation.

Having stopped your vehicle immediately you realize your mistake can save you greatly. What you have to do is completely drain the diesel off the gas tank.

You also have to completely drain all the injectors, the fuel rails, and the fuel lines. If you have never drained a car fuel before, seek a skilled technician assistance.

Accidentally Put Gas Instead of Diesel

Immediately you come to the realization of your mistake, safely park and stop the car. All the fuel has to be drained out as soon as possible. Adding regular gas to diesel can be catastrophic because of the different chemical properties of gas and diesel.

Mixing gas and diesel can result in destroying the vehicles fuel injector system, you are likely to experience misfires, or your engine can experience knocking. In the end, your engine can be completely destroyed.

Also, the engine can have reduced efficiency whereby you will have to repair or replace the engine. The cost can of fixing an engine can drain your pocket since you are likely to experience one problem after another due to the impact of fuel mixing.

Accidentally Put Premium Instead of Gas

There is nothing much to worry about accidentally putting premium fuel into a vehicle that uses regular fuel. Since premium fuel has much higher octane levels that regular gas, no significant damages will occur.

On the contrary, you are likely to experience some benefits. Find out more on what happens when you accidentally put premium in a gas car?.

Accidentally Put 89 Instead of 91 Gas

Since 89 gas is of much lower octane levels compared to 91 gas, significant damages will occur to your engine. An engine designed to burn 89 gas cannot effectively burn 91 gas.

A much reduced efficiency will be experienced. Stop your vehicle immediately and find a technician to help you drain the fuel system.

Accidentally Put Gas Instead of Premium

As soon as you realize you have mixed gas into a premium vehicle, park safely and stop the car. All the fuel has to be drained before further damage occurs in your engine.

In fact, you are likely to start experiencing some unusual noises when your car starts burning gas instead of premium. A rattling noise probably your engine can start knocking.

In worst case scenario, your engine will knock. If you are lucky enough, a modern vehicle engine system can automatically detect the fuel change and try to reduce the engine performance in an attempt to minimize significant damage from occurring.

You need to contact a technician to help solve your problem since it involves a lot of technical skills to bring back your car engine to its near initial optimum state.

Read more about what happens when you put regular gas on a premium car?

Wrong Gas In Car Symptoms

Sometimes, you may not even notice that you have put the wrong fuel in your car. In fact, you may have already start driving off to continue with your road trip.

However, here are some tips on how to know if you put the wrong gas in your car, you are likely to experience

  • Rattling noise
  • Extra running of the engine even when you have shut down
  • Problems starting up the engine
  • Engine knocks, it stops running
  • Weird speed fluctuations you did not initiate
  • Reduced responsiveness when stepping on accelerator
  • Warning light in engine illumination indicator
  • Lower fuel economy
  • More emissions
  • Idling can be rough
  • Destruction of the fuel filter

What To Do When You Put Wrong Fuel In Your Car

In most cases, you are less likely to know the potential impact from mixing up the fuels. In the instance you are not sure whether or not your engine will be in trouble, stay safe by following this best practices:

  1. If you has already embarked on your trip, park safely and stop the car
  2. Disconnect your battery if you can, if you can’t leave it that way.
  3. Your fuel system needs to be drained
  4. If you have no expertise, do not start what you cannot complete.
  5. Tow your vehicle to garage or to a place where your technician will be
  6. At no given circumstance should you ignite you engine unless when recommended by your technician.
  7. Technician will drain your fuel system including the gas tank, fuel injectors, fuel lines, and fuel rails, then replace the fuel with the recommended fuel.


I accidentally put the wrong gas in my car is a common experience. Anyone can do it. However, be sure to know what to do when you put the wrong gas in your car. Mixing fuel can have varying impact and some could completely destroy your engine if you do not rectify the wrong gas in car symptoms. However, mixing premium and gas can potentially be beneficial. If uncertain of the impact of putting wrong fuel in your car, turn of your vehicle and tow it to a technician.

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