Disclosure: I received free samples of Wynn’s and Halfords fuel system cleaning products from Halfords for this article. I did not receive any payment and was not required to write a positive review.
Drivers often take care to ensure that the visible parts of their car are kept clean, but what about the engine and fuel system? Although regular servicing should prevent any serious problems, your car’s fuel system won’t stay like new forever.
Deposits can build up in the fuel system and combustion chamber, and inside the injectors which control the flow of fuel into the engine. This can increase emissions and cause fuel consumption to rise.
Obviously this kind of issue is more of a problem on older vehicles. It’s also likely to be more of a concern with cars that are used for lots of short journeys from cold, as engines operate less efficiently when used in this way.
The good news is that if you think your car may be affected, there are various ways you can try to clean out your fuel system without having to do any mechanical work.
Fuel tank additives
Car maintenance stores such as Halfords almost always sell a range of products designed to clean your fuel system or reduce exhaust emissions. For example, Halfords stocks Wynn’s Xtreme Petrol System Clean and Halfords’ own-branded Petrol Emissions Cleaner. There are equivalent products for diesels, too.
These products are pretty simple to use: simply add to your fuel tank and drive. Each product has slightly different usage instructions relating to how much fuel should already be in your tank, but that’s about all.
As far as I can tell, the main ingredient in these products is kerosene. Halfords’ diesel and petrol emissions cleaner products both state that they contain “odourless kerosene”. The Wynn’s petrol system cleaner I tried doesn’t say what it contains, but judging from the smell it’s something similar.
In all cases, once added to your car’s fuel tank, these products simply work their way through the fuel system, cleaning as they go. If your car has previously had problems passing the MOT emissions test, then adding a bottle a couple of weeks before the test may be worthwhile.
We say: These products are intended to help maintain and restore your car’s original performance. They are not performance-enhancing products. They don’t increase the octane rating of petrol, for example. What they may be able to do is help clean injectors and reduce deposits that may have formed in your car’s fuel system.
I’ve tried a bottle of Wynn’s in my six-year old car. I haven’t seen any effect yet, but any difference would only be very slight. If you find your car feels more sluggish than when it did a few years ago or see fuel consumption getting worse, it may be worth a try.
Products mentioned (from halfords.com/motoring): Wynn’s Xtreme Petrol System Clean (£7.99/325ml @ Halfords) & Halfords Diesel Emissions Cleaner/Petrol Emissions Cleaner (both £14.99/500ml)
Is premium fuel an alternative?
You may be wondering whether there is anything you can do to keep your fuel system clean and prevent deposits building up.
One solution is to regularly use products such as the Wynn’s and Halfords cleaners I’ve mentioned above. However, some people believe that using premium road fuels such as BP Ultimate and Shell V-Power can have a similar effect.
These fuels are available in petrol and diesel versions and usually cost 3-5p per litre more than standard unleaded and diesel. In return for this you get fuel with a higher octane (petrol) or cetane (diesel) rating and a high-quality package of cleaning agents.
So there are two attractions: without getting into technical details, fuels with a higher octane or cetane rating should maximise performance from petrol or diesel engines respectively. What this implies is that your car will accelerate slightly harder — or alternatively you can accelerate at the same rate for less effort, which should reduce your fuel consumption.
The second attraction is that the cleaning agents in these premium fuels should help keep your fuel system and engine free of deposits. This should mean that performance, fuel consumption and emissions don’t get worse with age.
If you’re still undecided, you can read more about this in Is all petrol & diesel the same? It’s the most popular post I’ve ever written on this website, with more than 100 comments from readers, some of whom have very strong opinions about different fuels!