The Drive Belt and pulleys transfer power from the engine crankshaft to the alternator, A/C compressor, and power steering pump, while both the engine coolant pump and engine cooling fan are electric. Inspect the belt with the engine off; if it shows signs of wear, cracking, glazing, or missing sections, replace it immediately. To minimize the risk of belt failure while driving, replace the belt every four years. When a new belt is installed, keep the old one in the trunk for emergencies. Excessive engine movement due to a defective left side engine mount can cause Drive Belt damage, often from contact between the power steering pump pulley and the front axle carrier. The belt may dislodge from pulleys or break when driving over curbs, speed bumps, or at high speeds, particularly in N54 turbo models. If any damage is found to the Drive Belt, power steering pump pulley, or front axle carrier, replace these components along with the left engine mount using updated parts. To prevent electrochemical corrosion to aluminum-magnesium alloy engine components, avoid using steel fasteners and opt for aluminum fasteners instead. Test fasteners for aluminum composition with a magnet for reliable identification, replace aluminum bolts each time they are loosened, and adhere to torque instructions, including angle of rotation specifications, when installing aluminum fasteners.