The recommended oil grade for a 2009 Ford Falcon XT depends on the engine it has and the climate you live in. The owner's manual is the definitive source for this information.
Look in your owner's manual for the recommended oil viscosity (like 5W-20, 5W-30, 10W-30, etc.). The manual will likely specify different viscosities for different temperature ranges. Using the incorrect oil viscosity can harm your engine.
