Car Mechanics (UK)
FUEL-BORNE ADDITIVES – DIESEL
Additional chemicals can be added to diesel fuel, which survive the combustion process and end up in the DPF that encourage soot combustion at lower temperatures, reducing the risk of blockage. These fuelborne additives (which are also referred to as catalysts) can be dosed manually or automatically. Automatic systems are fitted to many PSA Peugeot/citroën/ds cars, as well as various Ford, MINI, Volvo and Mazda models, where a cerium-based additive (referred to as Eolys) is stored in either a pouch, or a separate five-litre tank. In most cases, an onboard computer injects the correct quantity of additive into the fuel tank after every fill-up. This additive needs to be replenished at various service intervals and the relevant ECU reset afterwards.
We investigated these systems in the September 2016 issue of As then, we advise that you use genuine fluids only, because several aftermarket fluid suppliers would not substantiate their claims of compatibility, when we asked.
Usually, when the owner experiences an issue with premature DPF soot blockage, fuel-borne additives can be bought off-the-shelf and introduced into the fuel tank manually to promote soot combustion. However, you should follow dosing instructions carefully. Certain well-meaning owners mistakenly believe that using more additive is a good thing, but overdosing can cause the soot within the DPF to combust too quickly, resulting in thermal runaway, because the DPF cannot regulate the temperature of the burning particulates. Either the DPF’S internal ceramic monolith, or the outer casing, will melt. Should the latter occur, red-hot particles could ignite material on the ground, which could cause a serious fire.