The best oil for a 2002 Chrysler Town and Country with 204,000 miles is 5W-20 motor oil. This is because of the vehicle's age and mileage. The 2002 Chrysler Town and Country has a 3.3L engine that requires 5W-20 motor oil with a viscosity index of 10W-30 or 5W-30. The 5W-20 oil is recommended for optimal engine performance and protection in high temperatures and cold climates. It also helps improve fuel economy and reduce emissions.