Liqui moly 5156 pro line diesel system cleaner 500ml liqui moly 5156 p this pro line diesel system cleaner 500ml from liqui moly has been developed for all aspirated and turbocharged engines reducing pollution emissions and optimising smoke concentration before the exhaust test p p the liquid cleaner performs a number of tasks such as cleaning the injection nozzles and the fuel system of any damaging deposits preventing injection needles from seizing and resinifying and optimising the