Deposits are a natural by-product of combustion and, without preventative maintenance, accumulate over time. Proof that all manufacturers recognise that their cars are vulnerable to deposit issues is documented in a publication produced by the engine manufacturers called the 'World Wide Fuel Charter'.

This document states "even good quality gasoline can lead to deposit formation. Such deposits will increase engine-out emissions and affect vehicle performance."

The fact is, because modern engines are so tightly engineered, and because of the precision with which fuel/air mixtures are calculated and delivered, removal of carbon deposits is even more critical. Fuel, no matter how good, will always release carbon through combustion. There are many areas where carbon impacts on the smoothness and efficiency of an engine. Tiny amounts of deposits are all it takes to disturb the critical spray pattern of an injector whilst valve deposits interfere with air/fuel flow, deposits in EGR valves cause a loss of power and increased emissions and deposits on O2 sensors means the ECU cannot calibrate the fuel air mixture accurately.

So what can motorists do?

Replacing EGR valves, the Diesel Particulate Filter or simply paying more for premium fuel because of poor performance can be a very expensive exercise, so any alternative solution that can remove deposits from components and systems is a welcome offering. Fuel system cleaners as they’re known are easily applied with the motorist pouring a can straight into the fuel tank at next fill-up. One of best known of these is BG44K (and its diesel equivalent BG 245). These offer cost-effective solutions to the problems of deposits and use high quantities of the chemistry identified by the WWFC as the effective treatment for removing hard baked carbon. Oil system service products such as BG's high-quality Engine Performance Restoration (EPR) can restore performance even more significantly but are best applied by a professional at a vehicle’s annual service point.