* Oil Viscosity: Your owner's manual likely specifies a viscosity range, such as 5W-20, 5W-30, or 10W-30. Given its age, a slightly thicker oil like 10W-30 might be preferable, especially in warmer climates, to provide better protection against wear and tear on older engine seals. In colder climates, stick with a 5W-30. Always check your owner's manual for the recommended range.
* Oil Type: The 1998 Lincoln Town Car likely uses conventional oil unless it's specified otherwise in the manual. However, synthetic blend oils offer a good balance of performance and cost-effectiveness compared to fully synthetic oils. Fully synthetic is an option, but unless you're driving in extreme conditions, a blend is likely sufficient and saves money.
* API Certification: The oil should meet or exceed the API (American Petroleum Institute) service classification specified in your owner's manual. This is usually something like "SN" or possibly even "SM" for older vehicles (check the manual). The letter indicates performance standards for the oil, and newer is generally better.
In summary: For a 1998 Lincoln Town Car, a 10W-30 synthetic blend oil meeting at least the SM API service classification is a good starting point. However, always, *always* check your owner's manual for the manufacturer's specific recommendations. The manual will have the most accurate and relevant information for your vehicle.
