The best petrol injector cleaners ranked by CAR 2026

► Petrol injector cleaners and how they work
► The best ones you can get on the UK market
► How often should you use them?

Keeping the fuel injection system clean from any build-up of carbon blockages is essential for the longevity of a petrol engine. One of the simplest ways you can keep an engine healthy is by emptying a bottle of petrol injector cleaner into the fuel tank. You can almost think of it as a deep cleanse to the internal organs of the engine.

But if you’re not clued up on how petrol injector cleaners work. Then don’t worry because it doesn’t involve the timely task of taking your engine to bits. In fact, much like with diesel injector cleaners, you don’t even have to open the bonnet at all.

It’s dead simple. You simply pour in the injector cleaner before you fill up with fuel. It works in conjunction with the petrol and cleans up the injectors as you drive normally. No spanners, no dirty hands, and no time away from the road.

Some cars from the 1970s and 80s run on fairly temperamental fuel injection systems. A regular clean could lessen the need to visit a specialist with a scary bill attached. For such cars, a regular dose of fuel cleaner is just as important as regular oil changes.

The best petrol injector cleaners

Below are our top five petrol injector cleaners. With real-world testing, we’ve got experience of some of these products ourselves, and can testify how well they’ve worked in our circumstances.

STP 5-in-1 Ultra Petrol System Cleaner

STP’s comprehensive 5-in-1 Petrol System Cleaner is designed to clean multiple components simultaneously as the engine runs. It’s designed to be used every 400 miles or so, which roughly equates to the distance an average petrol car can travel on a single tank of fuel. I’ve used this one a few times before. My usual process is to use a full bottle before filling up with Shell V Power and setting off on a long drive. These trips are usually three hours or longer, so using up all the fresh fuel along with the additive gives the engine a good clean.

What can I report? Quite simply, I’ve had no fuel-related issues. At any speed, the engine runs smoothly and ticks over as it should do. There’s no scientific way to test these cleaners without a lab and microscopic evidence, but surely having no news to report is the best news.

Bosch K-Jet Tronic systems can be notorious for issues; it was used on anything from VW Golfs to Ferrari Testarossas, so the fact I’ve had nothing to report on my W123 Mercedes must mean the constant use of additives has worked a treat.

Redex Petrol System Cleaner

On a more regular basis, I favour the Redex cleaner on the grounds of affordability. It’s only a fiver compared to around £11 for the STP product, yet the Redex cleaner has been proven to be effective for years. Two ‘shots’ equates to 250ml and four is 500ml, and I’ve been using it religiously on every fuel fill-up for the last five years or so.

How has it proven to be effective? In that five year period, the only fuel-related issue I’ve had was the fuel pump relay – and only electricity runs through that. So, it must be doing its job supremely well. As for value, an extra £5 or so is a little amount compared to the average fuel stop, and if it prevents future engine issues, it’s money well spent in my view.

Wynn’s Petrol Injector Cleaner

Designed to lubricate the fuel system as well as cleaning up the injectors, Wynn’s additive can be used to cure a rough idle. It can also protect the fuel system against corrosion, absorb condensation, and help reduce emission gases. It’s designed for regular maintenance use with one bottle treating up to 60 litres of fuel and recommended to be used for every 3,000km or third fill-up.

There is a drawback though; you can only get a 325ml bottle with no larger sizes available. So, if you have a large fuel tank that’s far more than 60 litres, this additive may not be as useful as others. Wynn’s also claims it can be used for petrol rated up to E20, so it should fare well with most E10 rated fuels in the UK.

Cataclean Fuel and Exhaust Cleaner – Petrol

Cataclean’s petrol system cleaner is more comprehensive than any other, as it’s designed to clean up to eight components. These being the fuel tank and lines, injectors, combustion chamber, valves, oxygen sensors, EGR valves, the catalytic converter and the PPF filter.

It’s ideal for modern cars with all these components attached, and it promises a noticeable effect in the cleanliness and subsequent smoothness of the engine. It is quite complex to use, though; Cataclean state that for the best results, you should pour in 500ml (a full bottle) per 15 litres of fuel every three months. This means you can’t use it like a regular additive as it claims to be a lot stronger than its competitors.

Wynn’s Formula Gold Petrol System Treatment

Wynn’s also offers a stronger version of its petrol system cleaner in the form of its Formula Gold product. It’s designed to be used after each engine service or every 7500km (more often, if needed), which is more occasional than the brand’s regular additive.

The Formula Gold is designed to clean all the important bits of an engine’s fuel system, including the injectors, intake valves and the combustion chamber. Like the other additives, this helps increase the longevity of the engine and makes it perform at its best.