The Best Fuel Injector Cleaners for Petrol and Diesel Engines

We use affiliate links and may receive a commission on purchases. Read more here.

Fuel injectors are an integral part of any vehicle’s engine. Their main purpose is to deliver the right amount of fuel to the combustion chamber at the precise moment, thus keeping the engines running.

Like most engine parts, fuel injectors are exposed to dirt and carbonization and can develop clogs over time if not maintained properly. While this won’t stop your car from running, it will affect its performance and fuel efficiency among other things.

Luckily, the problem can easily be solved by using a fuel injector cleaner. Aside from keeping your entire fuel system clean, these helpful additives can also save you plenty of money in maintenance and unwanted potential repair costs.

Best Overall: Red Line Complete SI-1 Fuel System Cleaner

As its name would suggest, the Red Line Complete SI-1 Fuel System Cleaner provides a complete set of fuel treatment additives. It doesn’t only excel at cleaning fuel systems or preventing corrosion but provides much-needed upper cylinder lubrication as well.

Furthermore, the Red Line Complete SI-1’s formula eliminates the need for high-octane gasoline by reducing the need for octane by up to two points.

Suitable for all kinds of engines (old and new) and applications such as cars, trucks, motorcycles, marine engines, etc, the Red Line SI-1 is as versatile as a fuel injection cleaner can be.

It should clean out close to 100% of gunk buildup in a single treatment and comes in 443 ml bottles that typically serve as a measure for one tank. Aside from a single bottle, the Red Line SI-1 comes in two-pack, six-pack, and a dozen-pack packaging. Safe for continual use, it’s recommended after every 5,000 kilometres or so.

Pros:

  • Highly versatile and efficient
  • Contains synthetic upper cylinder lubricant
  • Eliminates the need for high-octane gasoline

Cons:

  • Moderately expensive

Best Fuel Injector Cleaner for Petrol Engines: Nulon Pro-Strength Petrol System Extreme Clean

The Nulon Pro-Strength Petrol System Extreme Clean is designed specifically with petrol-burning engines in mind. Containing the polyetheramine formula, it’s extremely effective at dissolving the obstinate carbon sediments.

Aside from cleaning the fuel injectors, combustion chambers, intake valves, and manifolds, the Nulon Pro-Strength also helps the engine achieve better throttle response, smoother idle, efficient running, and helps reduce fuel consumption.

It comes in a 500 ml bottle that’s sufficient to treat up to 60 litres of petrol. It’s recommended to use it every 10,000 kilometres.

Pros:

  • Highly efficient
  • Based on the polyetheramine formula
  • Affordable

Cons:

  • Not suitable for diesel engines

Best Fuel Injector Cleaner for Diesel Engines: Lucas Upper Cylinder Lubrication & Injector Cleaner

The reason this is one of the best diesel engine products on the market lies in its ability to lubricate various engine components and neutralize the harmful effects of ultra-low sulfur diesel fuels such as corrosion, sludge buildup, etc. It also eliminates the need for higher octane fuel.

The smallest container the Lucas Upper Cylinder Lubrication & Injector Cleaner comes in is 155 ml, and it’s enough for one tank or up to a maximum of 95 litres of fuel. It also comes in larger 946 ml and 3.8 l packaging.

Although this is our pick for diesel engines, the Lucas Upper Cylinder Lubrication & Injector Cleaner works equally well with petrol-burning engines – old or new, with carburettors or direct injection.

Pros:

  • Highly versatile
  • Eliminates the need for high-octane gasoline
  • Neutralizes harmful ULSD fuel effects

Cons:

  • Not strong enough for once-a-year use

Rislone High-Performance Injector Cleaner

The Rislone High-Performance Injector Cleaner is a fuel additive designed for both petrol and diesel engines. It’s also suitable for both new and older vehicles.

The Rislone fuel injector cleaner is designed to clean and lubricate various engine components and reduce carbon buildup. In turn, your engine will restore lost power and experience an increase in fuel economy. Moreover, the product helps with rough idling and hard starting.

A 177 ml bottle will treat up to 76 litres of fuel and won’t harm emission control components such as catalytic converters, oxygen sensors, or diesel particulate filters.

Pros:

  • Highly versatile
  • Lubricates the engine components
  • Inexpensive

Cons:

  • Requires continual use for best results

Liqui Moly Petrol Injection Cleaner

Made specifically for petrol engines, the Liqui Moly Petrol Injection Cleaner isn’t as versatile as other products. However, it more than makes up for it by serving all kinds of old and new gasoline engines and by generally being affordable.

The German-made product is one of the better fuel cleaners on the market and provides all the benefits a fuel injection cleaner is supposed to – from smoother and more pleasant engine operation to increased fuel economy.

Liqui Moly comes in a 300 ml bottle that’s good enough for 25 litres of gasoline. It’s suitable for both the modern-day turbocharged or naturally aspirated EFI engines or the older carby-driven ones.

Pros:

  • Quick and efficient
  • Suitable for turbocharged engines
  • Affordable

Cons:

  • Not suitable for diesel engines

Fuel Injector Cleaner Buying Guide

If your vehicle is experiencing a drop in power or fuel economy, it’s a high probability that your fuel injectors are clogged. Luckily, this is an easily rectifiable issue that won’t break the bank and can be done by anyone. All you’ll need is a quality fuel injector cleaner. But before I explain how the fuel injector cleaners work, let’s first dissect the fuel injectors themselves.

What are fuel injectors?

Every modern vehicle has an engine based around fuel injection (typically direct injection) technology regardless of the type of fuel it’s using. Fuel injectors are one of the most important and delicate parts of the powertrain’s fuel system that introduce the fuel into the combustion chamber via a fuel pump. They do so by atomizing the fuel thanks to their small nozzle(s) to allow it to seamlessly mix with air. The air-fuel mixture is then ignited, and the process is repeated time and again to keep the engine running.

Fuel injectors are constantly working under high pressure and require almost sanitary conditions to run smoothly. Lower quality or contaminated fuel is going to put them under additional strain. Furthermore, most fuel nowadays contains traces of water and different fuel additives like ethanol alcohol to boost its octane rating. Needless to say, neither of these are friendly towards fuel injectors.

The main adversary of the fuel injectors, however, is carbon buildup. Most of the carbon will leave the engine through the exhaust system, but some traces will remain. Regardless of how meticulous you are when it comes to engine maintenance, carbon deposits will develop over time – usually in the combustion chamber, in the fuel injector itself, around the intake valves, around spark plugs, etc.

This is where a fuel injector cleaner comes in handy.

What is a fuel injector cleaner?

A typical fuel injector cleaner is a mixture of chemicals revolving around polyetheramine or PEA. This nitrogen-based solvent doesn’t only excel in cleaning built-up carbon deposits but can withstand extremely high temperatures typical for the combustion chambers of both petrol and diesel engines alike.

Once the fuel injector cleaner has been mixed with fuel, it passes through the entire fuel system dissolving carbon deposits along the way and restoring the engine to optimal working condition.

Benefits of fuel injector cleaners

Regardless of their type, the benefits of using fuel injector cleaners are numerous. Below are some of the most important.

Better fuel economy

By cleaning out the carbon deposits in your fuel injection system, the fuel injector cleaners will also increase your car’s overall fuel efficiency by a slight margin. Over time, however, this adds up, and you’ll soon note the difference.

Improved performance

Carbon buildup can have a detrimental effect on performance, as well as gas mileage and fuel injector cleaners can help the engine reach and maintain its full potential.

Lower emissions

Cleaner combustion also means lower emissions, and although the differences aren’t too significant, you’ll do the environment a favour – especially in the long run.

Lower noise levels

A clean engine will run smoother and be less noisy in the process.

Lower maintenance costs

Needless to say, keeping your fuel system clean will keep your engine running smoothly and, in turn, potentially save you some money in maintenance expenses.

What to look for in a fuel injector cleaner

Here are some of the most important things to pay attention to when selecting a fuel system cleaner for your car.

PEA

As the most important ingredient of any quality fuel additive intended for the carbon deposit breakdown, you’ll want to look for a product that contains polyetheramine. PEA’s ability to dissolve debris at a molecular level is simply unmatched.

Versatility

Plenty of fuel injector cleaners can service both petrol and diesel engines, as well as modern cars and those from the bygone era. However, some are designed for specific types of engines. If you’re opting for the latter, make sure you choose the right product for your vehicle.

Lubrication

Some products also contain lubricants for various engine parts. Not only do they make the cleaning more effective, but also protect the engine in the long run.

Amount of fuel treated

A larger bottle and a lower price tag don’t necessarily translate to a better deal. Most manufacturers will state how much fuel their product can treat, and you should probably consider that information when making a choice.

Container

Don’t underestimate the quality and shape of a container. The most prominent fuel injector cleaners come in specifically designed containers for easy pouring.

How to use a fuel injector cleaner?

Here are the step-by-step instructions on fuel injection cleaner usage.

1. Select the right product for your car

Choosing the right fuel injector cleaner depends on the type of car, and more specifically, the type of engine it’s fitted with. Most of them work with any type of fuel, but some will be either petrol or diesel-specific. Furthermore, if your car has a turbocharged or supercharged engine, check the manufacturer’s recommendation before proceeding. It’s always advisable to read the instructions on the bottle before making the final decision.

2. Measure the right amount of fuel injection cleaner

Most bottles are designed to provide enough fuel injection cleaner for one gas tank, but not all vehicles are made the same. Larger SUVs and utes usually come with a larger fuel tank and will require more than one bottle of additive.

3. Bring your fuel level as low as you possibly can

While a fuel system cleaner works even with a full tank of gas, it’s advisable to pour it into an empty tank for the best results. Since you’ll need to refill your tank with gasoline, later on, it’s best to perform these tasks at a petrol station.

4. Pour the fuel injector cleaner into the fuel tank

5. Fill the gas tank with fuel

6. Empty the gas tank by driving your car

For the fuel system cleaner to reach the fuel injectors, your car either needs to run or burn through the entire tank while idling which, you’ll agree, is absurd.

A couple of ways to boost the effectiveness of the injector cleaning are to either drive your car at higher rpm’s or drive it at higher speeds (or both). That way, the pressure in the fuel system will be higher, and the fuel injector cleaner will have optimal conditions to dissolve the buildup of carbon with ease.

If you don’t notice a difference in your vehicle’s operation after the entire fuel tank has been emptied, your fuel injectors are probably extremely dirty. In that case, it’s advisable to repeat the process during the next fill-up.

Fuel Injector Cleaner FAQs

Will a fuel injector cleaner increase my car’s fuel economy?

In most cases, it will, but different engines, different levels of clogging, and different types of product will all yield different results.

Can a fuel system cleaner damage my engine?

All reputable fuel additives, including fuel injector cleaners, have been thoroughly tested on all kinds of engines, and the probability of them damaging an engine is highly unlikely.

Can fuel injector cleaners be used in older cars?

Yes. Fuel injector cleaners can be used in cars old and new, with carburettors or direct injection, with natural aspiration or forced induction. Do read the instructions before using them, just in case.