Some 2018 Mustang GT350 vehicles may exhibit what appears to be an oil leak originating from the engine oil drain plug, especially at the time the vehicle has been delivered to the dealer or during PDI. Before attempting any repairs to resolve this, it's advised to confirm that there is actually a persistent oil leak. The normal production process used to build the engine may result in a small amount of residual oil on the oil pan near the drain plug. Additionally, the design of the drain plug may cause a small amount of oil to be trapped in the drain plug bore after an oil change, and this oil may seep out a short time after an oil change. This may also cause the appearance of a persistent leak from the drain plug. No action needs to be taken unless the leak persists.
