Redex FAQs: Your Questions About Fuel Additives Answered

Fuel additives have been a staple of car care for decades – you even used to be able to get a shot of Redex added to your tank at the petrol station when you filled up.

If you’re new to fuel additives, you might have questions about how they work, what benefits they offer, and whether they’re compatible with your type of vehicle.

Our Redex Club has asked us some questions so we got our experts in the lab to answer them and some other common FAQs we get, to help you buy and use Redex.

If I use Redex petrol system cleaner in a diesel car, will it damage the engine?

While using the wrong fuel additive in your engine won’t damage it, the product won’t work properly because the formulas used for each type of fuel are different.

We only recommend using petrol Redex products for petrol vehicles and diesel Redex products for diesel vehicles. The two fuels act differently in the engine, so we use lab-tested formulations to guarantee great results for petrol, diesel and hybrid fuel systems.

How do I know how much Redex to add to my car’s tank?

Redex is designed to be easy to use, with clear labelling telling you how much of a bottle to use in different fuel tank sizes – so you can just follow the on-pack instructions. For example, the 250ml petrol system cleaner treats two tanks, so just add half the bottle each time you fill up with fuel. We’ve made this easy, too, with marks on the edge of the bottle to show you the correct dosage. If you accidentally add more though don’t worry, it won’t cause any damage!

If you haven’t used Redex system cleaners before, we’d recommend doubling the dose for the first couple of tanks to ensure a quick and complete clean, or use Advanced System Cleaner.

Can I use Redex in a motorcycle? If so, how much should I use?

Yes, you can use Redex in any combustion engine. Our fuel additives are suitable for use in cars, vans, motorbikes, tractors or anything with a petrol or diesel engine, and even hybrids.

In terms of how much you should use in a motorbike engine; standard Redex fuel system cleaners should be dosed at around 2.5ml per 1l of fuel. So, for a standard 15l motorbike fuel tank, you’re looking at around 38ml of system cleaner per full tank of fuel (roughly half a standard shot).

Closeup of Motorbikes lined up

Can I use Redex and AdBlue® together?

Yes, you can use Redex fuel system cleaners on any vehicle fitted with an exhaust treatment system such as Adblue® or a lean NOx trap as they treat different parts

Redex fuel additives are added to the fuel tank to clean the system while. AdBlue® should be added to the AdBlue® tank to help reduce NOx emissions in diesel cars. The two products are safe to use together, just make sure you add them to the right tanks.

What is the difference between the Professional DPF Cleaner and Complete Diesel System Cleaner products?

The products target different parts and have been developed to solve specific problems.

Redex DPF Cleaner specifically helps your car’s DPF Cleaner to either clear soot build up or prevent it from becoming blocked. It works in two ways; it helps create a ‘cleaner burn’ during the combustion process, leading to less soot build-up, and also lowers the burn-off temperature of any soot present in the system. It’s a great way of removing the stress of your car’s DPF warning light coming on mid-drive. Read our guide to diesel particulate filters, here.

Redex Diesel System Cleaner ensures the essential components of the fuel system are clean, specifically the injectors. Clean injectors mean better fuel atomisation, leading to engine longevity which in turn gives more power and better fuel economy.

If I use Redex System Cleaner regularly, do I still need to use Redex Advanced Fuel System Cleaner every 3,000 miles, and if so, why?

Yes. It’s a good idea to give your engine a deep clean on the inside every now and then, as this will make sure it’s always running efficiently. The Redex Advanced Fuel System Cleaner products do just that. Ensure your fuel system is in top condition through the regular use of Redex products. We recommend using the system cleaner in every tank of fuel, and the advanced product every 3,000 miles or every few months, whichever comes first.

Closeup of a Dashboard

I have a Mitsubishi Shogun – is there a particular product you’d recommend adding to its diesel tank every few months?

We’d suggest using Redex diesel system cleaner in every tank, and the advanced product every 3,000 miles or every few months. If it’s young enough to have a DPF fitted, regular use of the Redex DPF cleaner can avoid costly repair or replacement bills, too.

Can you recommend a product for a 20-year-old Chevy Silverado with a 5l petrol engine and 170,000 miles on the clock?

We’d recommend petrol system cleaner and petrol booster in every tank, and the petrol advanced product every 3,000 miles or every few months. The system cleaner will make sure the fuel system doesn’t get soiled/dirty and the petrol booster will ensure you’re getting maximum performance from the 5L engine. Then the advanced product will give a deep clean, keeping the engine working at its best for longer.

How does the DPF cleaner work?

Redex DPF Cleaner lowers the burning temperature of the soot trapped in your car’s particulate filter system, meaning that it burns away more efficiently during regular day-to-day driving. This means you don’t have to drive for long distances to get your engine up to a high temperature, which is normally how you keep a particulate filter regenerating.

Redex DPF cleaner contains a nano-metal oxide catalyst, which reduces the temperature at which the soot burns and is able to fit through the small holes in the filtration system – cleaning the blockage.

We’d recommend using DPF Cleaner during normal everyday driving to prevent the DPF warning light from coming on. If you’ve left it too late, however, the product can be used to quickly clear the blockage, and the dashboard warning light should switch off.

Closeup of Diesel Pumps at a Petrol Station

Can I use Redex in my classic car?

Yes, you can. Redex is designed to keep cars on the road, regardless of age. We’ve developed a range of products for different engines, including a specialist Lead Replacement formula specifically designed for vintage cars that run on leaded petrol.

Since leaded petrol was removed from fuelling stations, classic car owners either have to use unleaded or convert their cars to run on a different type of fuel.

Redex Lead Replacement maintains good engine performance by stopping valve seat recession, so it protects the fragile components within classic engines. It’s also safe to use other Redex products, such as our Petrol System Cleaner, in a classic car, and this help will keep it in the very best condition, removing harmful deposits to help improve engine life.

Redex DPF cleaner contains a nano-metal oxide catalyst, which reduces the temperature at which the soot burns and is able to fit through the small holes in the filtration system – cleaning the blockage.

We’d recommend using DPF Cleaner during normal everyday driving to prevent the DPF warning light from coming on. If you’ve left it too late, however, the product can be used to quickly clear the blockage, and the dashboard warning light should switch off.

Which Redex product should I use in my car?

Finding the Redex product that’s compatible with your car is straightforward. You can use the Which Redex Are You? Chart to quickly find the product that suits your car, engine, mileage and refuelling schedule. The page also has lots of supplementary information to help steer you in the right direction.

If in doubt, however, you can always get in touch with the Redex team and we’ll be happy to help. You can do this through our Redex Club Facebook Group or by visiting our contact page.

Are there any models that Redex cannot be used in?

Redex can be used in any combustion engine, and our products are suitable for cars, vans, motorbikes, tractors, trucks, and just about any vehicle with a petrol, diesel or hybrid engine – even lawnmowers!

Someone Mowing their Lawn

How often should each of the Redex products be used?

Here’s a list of each Redex product and the interval at which they should be used:

  • Redex System Cleaner (Petrol and Diesel) – Use whenever you fill up the tank, or every other time you fill up, depending on mileage and the age of the car.
  • Redex Power Booster (Petrol and Diesel) – Use whenever you fill up the tank to improve your car’s power and maximise performance by increasing the cetane/octane rating.
  • Redex Lead Replacement – Use every tank to protect your car’s classic engine from corrosion.
  • Redex DPF Cleaner – Use every 2-3 tanks or when the DPF warning light comes on.

What happens if I use more than the recommended dose?

Adding too much Redex won’t cause any damage to your car or interrupt the combustion cycle. Plus, it’s hard to use more than the recommended dose because of how the bottle is designed, with clear marks indicating a single dose. The more you add, the higher the concentration within the fuel so you’ll get a more intensive clean.

Are Redex Fuel Additives Safe to Use with E10 Petrol?

Yes, all our petrol fuel additives are safe to use with E10, so you can continue to enjoy the same performance-enhancing benefits that a shot of Redex can bring. E10 simply contains more ethanol than the outgoing E5 blend, so it doesn’t affect the way our fuel additives work to keep your engine clean and performing at its best.

Can Redex lower emissions before my MOT?

Yes, and we actually have a specially formulated Pre-MOT product which will give an intensive clean and help to lower emissions which could help you to pass first time. Use it a few days before your test to give it time to work through the system. The Pre-MOT Emissions Reducer is available for both diesel and petrol. You can also use our Advanced products in the run up to an MOT, as they also help to lower emissions.

MOT Test Certificate

Do you still advise pouring some Redex down the spark plug holes?

No, we wouldn’t advise pouring Redex down the spark plug holes. Redex system cleaners are designed to be poured directly into the fuel tank, where they circulate through the fuel system and engine, removing deposits to optimise engine health.

Can you use Redex in a wet clutch engine?

Yes, Redex products can be used in all combustion engines, including wet clutch motorcycle engines.

How is Redex Diesel Particulate Filter Cleaner different from standard Redex additives?

Redex DPF Cleaner contains a nano-metal catalyst, which is specifically designed to reduce the temperature at which trapped soot in the particulate filter burns. Redex System Cleaner does not contain this catalyst, so you should use DPF Cleaner to keep the filter clear and prevent the DPF light from coming on. They work on different areas of the car, so you can also use them together safely.

Can I still add Redex to a half tank?

Yes, Redex is safe to use in a partial tank of fuel. For half a tank, you can add half a shot which is a doage of 2.5ml per litre of fuel. However, if you add a single shot by mistake, it won’t cause any harm and will get to work as normal, circulating through the fuel lines to remove dirt and deposits from the fuel injectors.

Will Redex Clean My EGR Valve?

Redex is unable to clean a vehicle’s EGR valve. Instead, our petrol and diesel system cleaners focus on clearing debris and blockages from the fuel injectors, ensuring maximum efficiency in the engine’s cylinders during the combustion cycle.

Does Redex have a shelf life?

Redex products are designed and developed to the highest possible standards, so you can expect a shelf life of three years from the date of manufacture, if unopened.

Join the Redex Car Club

If you have a question about our products or want to catch up on the latest news and goings on from us, get involved in the conversation in our Redex Club Facebook group. This is a place for fans to chat about motors, mates and more, so join our group today.

For a better drive, use Redex. Our innovative fuel additives deliver performance and efficiency for every engine – visit our homepage to learn more.