This document specifies a multi-pass filtration test, with continuous contaminant injection and using the on line particle counting method, to evaluate the performance of diesel fuel and petrol filters for internal combustion engines submitted to a constant flow rate of test liquid. The test procedure determines the contaminant capacity of a filter, its particulate removal characteristics and differential pressure. This document is applicable to filter elements having a rated flow between 50 l/h and 800 l/h; however, by agreement between the filter manufacturer and customer, and with some modifications, the procedure is permitted for application to fuel filters with higher flow rates.