Switching Up Your Car's Fuel: A Diy Guide

Changing the type of fuel in your car can be a straightforward process, but it's important to ensure that your vehicle is compatible with the new fuel type to avoid any potential issues or damage. The first step is to check your vehicle's compatibility with the desired fuel, which can be found in the owner's manual or on the inside of the fuel filler flap. It's essential not to put the wrong fuel in your car as it can cause serious damage, especially if the ignition is turned on.

If you're switching from a higher octane fuel to a lower one, it's generally safe to do so without completely emptying your tank first. However, if you're upgrading to a higher octane fuel, it's recommended to finish the lower octane fuel before refilling with the new one to avoid blending. While it may not be necessary to drain your tank completely when switching fuel types, it's always a good idea to refer to your owner's manual for specific instructions or consult a mechanic if you're unsure.

Additionally, be mindful of the differences between petrol and diesel engines. Putting diesel in a petrol car is less serious than the other way around, but it's crucial to drain the fuel system as soon as possible in both cases.

Check your car manual for the recommended fuel type

Changing the type of fuel in your car can be a tricky process, and it is important to ensure that you are using the correct fuel type for your vehicle. The best place to start is by consulting your car manual, which will recommend the optimal fuel type for your car.

Your car manual will outline the minimum octane level required for your vehicle, and whether premium gas is recommended or required. Octane levels refer to the stability of the fuel, with higher octane levels indicating greater stability and resistance to pre-ignition. Regular unleaded gas, with an octane level of 87, is suitable for most cars, while some high-output engines require premium gas with higher octane levels, typically ranging from 91-94.

It is important to follow the manufacturer's guidelines in your car manual. Using a fuel with an octane level lower than what is recommended can reduce engine performance and may cause damage over time. However, if your car manual specifies regular-octane gas, you can safely use higher-grade fuels without any additional benefit to performance.

In some cases, you may wish to switch from premium to regular gas to save money. If you are considering this, it is important to consult your car manual to ensure that regular gas is suitable for your vehicle. Additionally, you may want to check if your car has been tuned for a specific octane level, as using a different fuel type may impact performance.

While it is not necessary to completely empty your tank before switching fuel types, it is recommended to use up as much of the existing fuel as possible to minimize the amount of mixing. This is because blending two different types of fuel can reduce performance, especially if the octane level is significantly different.

By following the recommendations in your car manual and choosing the appropriate fuel type for your vehicle, you can maintain optimal performance and avoid any potential damage to your engine.

You can switch fuel types without emptying your tank

It is not recommended to switch fuel types without emptying your tank. However, it is possible to do so, and it may be tempting if you want to avoid the hassle of draining your tank.

If you do decide to switch fuel types without emptying your tank, it's important to note that you may experience reduced performance and fuel economy. This is because the engine is tuned to run on a specific type of fuel, and using a different type can affect the way the fuel burns and how efficiently the engine runs.

In addition, mixing different types of fuel can also affect the octane rating. For example, if you have a quarter tank of 87-octane fuel and fill the rest with 91-octane fuel, the resulting blend will be lower than 91 octane.

It's also worth noting that while some people believe that premium fuel is just a marketing ploy by oil companies, others argue that it can provide benefits in terms of engine performance and longevity, especially in turbocharged or tuned engines.

However, it's generally best to consult your car's owner's manual or a trusted mechanic before making any decisions about switching fuel types, as doing so can potentially damage your engine.

If you do decide to switch fuel types, it is recommended to drain the tank as much as possible to avoid mixing different types of fuel. This can be done by running your car until the tank is close to empty.

Using a lower octane than recommended can damage your engine

While it may be tempting to save some money at the pump by using a lower octane fuel than the manufacturer's recommendation, it can be a false economy. Using a lower octane than recommended can cause serious issues with your engine, and it is always best to follow the manufacturer's guidelines in the owner's manual.

The octane rating on different grades of gasoline is a measurement of the fuel's stability. Higher octane numbers mean greater stability. The greater stability indicates the gasoline's resistance to pre-ignition and the fuel's ability to resist "knocking" or "pinging" during combustion. These sounds come from the air-fuel mixture detonating prematurely in the engine.

If your car is designed for regular-octane gas, you can safely use higher grades of gasoline. But there is little to no benefit to buying fuel with octane levels greater than what is recommended. However, if your car requires a higher octane than the fuel you are using, this can cause issues. Engines designed for regular-octane gas gain little to no benefit from using high-octane fuel, but using a lower octane than recommended can cause problems.

Using unleaded gas with octane levels lower than what the carmaker recommends can reduce performance and may cause damage over time. It might also void the vehicle's warranty. A lower octane fuel may cause pinging or pre-detonation. Not only will your combustion be less efficient, but you will also have less power and you can damage your engine.

Always follow your owner's manual guidance when choosing a type of gas. The fundamental rule of car maintenance is to follow the manufacturer's guidelines. It will show the minimum octane level for the vehicle and whether premium gas is recommended or required. Generally, do what the manufacturer outlines in the owner's manual, pay attention when filling up at the pump, and choose the right fuel for your car.

Diesel in a petrol car is worse than petrol in a diesel car

Putting diesel in a petrol car is worse than putting petrol in a diesel car. This is because diesel engines use the properties of diesel fuel as a lubricant. If diesel engines are run with petrol, parts like the fuel pumps will lose lubrication, and the resultant high-pressure metal-on-metal fragmentation will cause clogging and the breakdown of the injection lines.

On the other hand, diesel in a petrol car will make it run poorly, but it is less likely to cause actual expensive repair work. The lines and injectors will just need to be flushed afterward.

If you accidentally put the wrong fuel in your car, it is best to not switch it on and call a roadside assistance company to come and empty the tank.

Diesel engines can burn petrol, but petrol engines cannot ignite diesel. Petrol engines will fill the cylinders with diesel that won't burn and won't compress, which basically destroys the engine after a few revolutions.

It is worth noting that the diesel car market in the United States is relatively small, and diesel fuel is typically more expensive than petrol.

E10 fuel may damage older cars

E10 fuel is a blend of 90% gasoline and 10% ethanol. While it is becoming more and more popular as a fuel source, there are concerns about its impact on newer engines. This is because ethanol can cause corrosion and damage rubber and plastic components in the engine.

Ethanol is hygroscopic, meaning it can absorb moisture from the air, which can lead to corrosion. This can cause a build-up of deposits in the fuel system, resulting in poor fuel economy, reduced engine performance, and increased emissions. As such, it is not suitable for all cars.

Owners of classic, cherished, and older vehicles, particularly those from the early 2000s, are advised not to use E10 fuel. This includes some specific models, such as certain VW Golfs built as recently as 2004, and some mopeds, especially those with an engine size of 50cc or under. If you own a classic car, it is important to check with the manufacturer or a classic car association to see if your vehicle is compatible with E10 fuel.

If your vehicle is not compatible with E10 fuel, you can continue to use E5 fuel, which has a lower ethanol content. Most filling stations will still offer E5 as a premium option. While it is more expensive, it is important to use the correct fuel for your vehicle to avoid potential damage and increased fuel costs.

It is worth noting that using a single tank of E10 fuel in a non-compatible vehicle is not a major problem and is unlikely to cause lasting engine damage. However, prolonged use of E10 fuel in a non-compatible vehicle may cause harm and is not recommended.

Frequently asked questions