What Happens If You Put Wrong Gas In Car

Ever wonder what happens if you put the wrong gas in the car? This may seem like something of a freak accident, but this is something that actually does happen on a relatively common basis. What happens next generally depends on the type of fuel mix-up that occurred.

In some situations, it presents a minor issue that resolves itself. In other situations, it can cause major damage to your car’s engine.

So what happens if you put the wrong gas in your car? Here are some of the possible things that can happen, as well as what you should do in the event that it does.

1. What Happens if You Put Diesel Fuel in a Gasoline Engine

(diesel in petrol car)

As you may know, the composition of diesel fuel and gasoline are starkly different. So, you can realistically expect something terrible will happen if you somehow fill diesel into a gasoline engine. - diesel in petrol car

diesel in petrol car

Diesel is a type of fuel that is relatively difficult to combust, and virtually all gasoline engines are not designed to burn this type of fuel. Because of the inability of gasoline engines to use diesel as fuel, your motor will eventually shut off once all the remaining gasoline in the tank is consumed.

Placing diesel fuel in a gasoline engine is relatively uncommon because of the differences in the nozzles used for pumping these two types of gas. However, if it does happen, it is recommended that you turn off the engine as soon as you realize your mistake.

This is to prevent potentially serious damage to internal engine components. The solution is to drain out both the gas tank and the fuel lines.

While you can theoretically do this yourself, it is best to ask for professional help in draining your fuel lines.

2. What Happens if You Put Gasoline in a Diesel Engine

The differences between diesel and gasoline fuels become more pronounced in a diesel engine. In contrast to the gasoline engine, a diesel engine can sustain significant damage almost immediately after being filled with gasoline. This is because the qualities of gas are significantly different compared to diesel fuel. Gasoline is more combustible, meaning it will detonate much faster, causing misfiring, knocking, and potentially permanent damage to your engine.

Also, diesel fuel doubles as a lubricant, so you can expect friction inside the motor to be extremely high, resulting in more damage.

Wrong Gas In Your Car

Just like with gasoline engines, as soon as you realize that you’ve placed the wrong fuel, you’ll need to shut off your diesel car right away. From there, you’ll need to have both your gas tank and fuel lines wholly drained. This must also be done by a qualified mechanic, as improperly draining can still cause damage to your engine. Never force to drive your diesel car with gasoline fuel. Have it towed, if necessary, as the potential damage to your vehicle can end up being more costly than the price of towing. 

3. What Happens if You Put High-Octane Fuel on an Engine That Doesn’t Need It


What happens if you add premium gasoline to a car that doesn’t require it? This mistake is more common than other gas mix-ups because the fuel nozzles used are similar. Also, there are a lot of motorists who don’t necessarily know the difference between octane levels. Also, there is a prevailing belief that going for a higher octane fuel is better for your car as it boosts performance. But what exactly happens if you put high-octane fuel in a vehicle that doesn’t need it?

The results generally depend on the type of engine you are running, but commonly, this neither helps nor hurts your car’s performance or durability. In some cases, going for higher-octane fuel does boost performance because of more straightforward burning. However, for most consumer fuels, the power boost is not that significant.

Also, there are some engines that aren’t designed to burn premium fuel, resulting in lower power and fuel efficiency. However, this mistake should not cause significant damage to your car. Just fill your car with the right fuel the next time you fill up your car, and eventually, the problem will correct itself. 

4. What Happens if You Put Low-Octane Fuel on an Engine That Requires High-Octane Fuel

What happens if you add low-octane fuel in an engine that requires high-octane premium gasoline? Some people do this to “cheat” on fuel costs, thinking that doing this does not cause any problems with their car. However, mechanics will tell you that this fueling mistake is more fatal than putting higher-octane fuel in a car designed to run on low-octane fuel. This is because the side effects of such filling errors can destroy your motor.

If you fill up an engine designed to run using premium gas with low-octane fuel, you will notice the effects almost right away. There will be a reduction of the engine performance, with the degree of losses depending on the octane gap.

Prolonged use of low-octane fuel will cause alterations in fuel detonation, which can lead to erratic combustion and damage to your engine’s internal components. It also leaves your engine prone to overheating. It is essential that you switch to premium fuel right away as soon as you can refuel your car.

What to do if You Put wrong gas in the car

Due to multiple reasons, filling up your car with the wrong fuel is a relatively common occurrence.

While such cases usually don’t end up causing serious and permanent damage to your engine, it is important that you avoid filling up the wrong gas in the car. In the event that it does happen, your mode of action depends on the situation.

For gas/diesel mix-ups, diesel in petrol car, a prompt drain is necessary to prevent internal damage to your car. In cases of filling up your car with the wrong octane of fuel, your car usually compensates so that no immediate damage may happen. However, it is important that you fill your engine up with the correct fuel right away.

If you experience any major issue (for ex., significant power loss, overheating, knocking, irregular noise), call your mechanic right away.

About the Author Simon Adams

Simon graduated with a Mechanical and Electrical Engineering Degree. He has over 20 years of servicing experience in both Japanese and German car dealerships. He now acts as a freelance mechanic's instructor for local schools.

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