Walk into any motor factors or browse any online retailer and you will find a bewildering array of fuel additives promising everything from improved economy to extended engine life. At Brookes Auto Repair, customers regularly ask us whether these products are worth buying. The honest answer is: it depends on the product and the application.
Fuel System Cleaners
Detergent-based fuel system cleaners that are added to the fuel tank are among the more credible additive products available. Over time, fuel injectors, inlet valves, and combustion chambers accumulate carbon deposits that can reduce efficiency and cause running problems. A quality fuel system cleaner used periodically can help to dissolve these deposits and restore cleaner combustion. They are not a substitute for a professional fuel system service on a vehicle with significant build-up, but used regularly as maintenance they have a reasonable evidence base.
Octane Boosters
Octane boosters claim to increase the octane rating of standard unleaded fuel. In practice, the concentration achievable by adding a small amount of additive to a full tank is modest — and unless your engine is specifically tuned to benefit from higher octane fuel, the effect on performance is negligible. Modern engines with knock sensors adjust ignition timing automatically to suit the fuel being used, reducing the potential benefit further.
Oil Additives
This is perhaps the most controversial additive category. Many oil additives claim to reduce engine wear, improve economy, and extend oil change intervals. The problem is that modern engine oils already contain carefully balanced additive packages formulated for specific applications. Adding aftermarket additives can disrupt this balance. Most vehicle manufacturers specifically advise against the use of supplementary oil additives.
The Bottom Line
A quality fuel system cleaner used as part of a regular maintenance routine is a reasonable investment. Most other additive claims should be approached with healthy scepticism. The best thing you can do for your engine is use the correct grade of oil, the recommended fuel, and stick to the manufacturer’s service intervals. At Brookes Auto Repair, we are always happy to advise on specific products. Visit brookesautorepair.com.
