Essential substances that lubricate, cool, and protect various components within a vehicle. Fluids, such as engine oil, transmission fluid, coolant, and brake fluid, circulate through the vehicle's systems, reducing friction, transferring heat, and ensuring proper operation. Grease, a thicker lubricant, is used in areas where sustained lubrication is required, like bearings and joints. Both fluids and grease are crucial for maintaining the vehicle's performance, longevity, and overall reliability.