Shell Helix HX5 motor oil uses special Active Cleansing Technology to help engines operate efficiently for a smoother and quieter drive. In studies carried out by an independent market research agency, a significant number of respondents felt that their cars were quieter after an oil change to Shell Helix HX5. The oil in a clean engine can flow more quickly to where it is needed and has improved access to surfaces, so the engine is better protected. Shell Helix HX5 goes on delivering its benefits from one oil change to the next. Shell Helix HX5 is specifically formulated for fuel-injection petrol engines with blow-by-gas recirculation. There are many formulations for different fuel types.