Prado with engine knocking and emitting a faint noise

I am offering you a 2004 Prado GX4, 4-cylinder, manual transmission, dual-range gearbox; mileage is approximately 500 km. The engine emits a faint knocking sound and the oil warning light is on. Body structure is excellent; rear assistance is required. Front and rear air conditioning, plus a refrigerator. The body shows noticeable imperfections in the fiberglass. Spark plugs and moving parts are original. Water pump, thermostat, radiator cap, original coolant, and heater core have all been replaced. Accident-free. Recently inspected. Interior shows visible signs of wear. All other aspects are in good condition. Ready for immediate transfer. Price ceiling: 15,000; no negotiations—save your time.