The Office of Defects Investigation (ODI) opened PE20-018 on November 5th, 2020, to investigate fuel leak allegations in vehicles equipped with fuel tank outlet flange Part Number AH229039AB. ODI based the investigation on six consumer complaints it had received and, using information gathered from RQ19-004, five field reports and 200 warranty claims in the subject vehicles. At the closing date of PE20-018, the number of related complaints received by ODI has risen to fifteen. In response to an ODI Information Request (IR) letter, Land Rover identified: 57 additional warranty claims (257 total), four additional consumer complaints (ten total), and five dealer field reports.Land Rover?s internal investigation identified a cyclic fuel pressure condition that led to cracks forming in the outlet flanges, resulting in fuel leaks. Fuel tank outlet flange revisions to the subject AH229039AB component increased the rigidity of the outlet flange in the area experiencing the highest stress. As Land Rover continued to assess field returned components, they identified cracks in the vicinity of subsurface voids in the subsequent AH229039AC and AH229039AD fuel tank outlet flanges.Based on the information gathered, Land Rover`s Recall Determination Committee (RDC) elected to recall vehicles with the subject fuel outlet flange and expanded the scope to include all vehicles equipped with fuel outlet flange Part Numbers AH229039AA, AH229039AB, AH229039AC, and AH229039AD. Land Rover will replace the previously listed part numbers with an updated designwhich reduces the pressures exerted on the fuel flange. Recall 21V-635 (covering MY2010-2013 Range Rover Sport and MY2010-2016 LR4 vehicles equipped with 3.0L V6 or 5.0L V8 engines) was reported to NHTSA on February 16, 2021. An interim owner notification letter was distributed in October 2021 alerting owners to the defect and the availability of like for like replacements until the remedy parts become available. Land Rover has indicated that remedy parts will become available in the second quarter of 2022. Correspondence from the fuel outlet flange supplier (Vitesco Technologies) indicated that the components at issue in this investigation were sold exclusively to Land Rover.This Preliminary Evaluation has been closed due to the recall issued by the manufacturer (NHTSA Recall 21V-635). The fifteen consumer complaints reports cited above can be reviewed at NHTSA.gov under the following reference numbers: 11122159, 11155570, 11156894, 11220260, 11255901, 11280630, 11337853, 11375884, 11383192, 11388329, 11420940, 11423024, 11428966, 11431744,11440020.