The amount of oil needed for a 1.25 Ford Fiesta petrol engine depends on the *specific* year and model of the Fiesta. There's no single answer. The owner's manual for your *specific* car will state the exact oil capacity.
Generally, the capacity is between 3.5 and 4.0 liters, but it could be slightly more or less. Do not rely on this range; check your owner's manual. Using the wrong amount of oil can damage your engine.
