* Consult your owner's manual: This is the most crucial step. The manual will specify the exact viscosity (like 5W-30, 10W-30, etc.) and the type of oil (conventional, synthetic blend, or full synthetic) recommended by Ford for your specific engine.
* Without the manual: For both engines, a 5W-30 oil is a common and likely suitable choice *if* your climate is temperate. If you live in very hot or very cold climates, a different viscosity might be better (like 10W-30 for hot climates or 0W-30 for very cold climates).
* Oil type: While the manual will dictate the best type, conventional oil was likely standard for that year, but synthetic blends or full synthetics are often preferred for their better performance and longevity. However, using a higher-grade oil than specified isn't harmful unless the manual specifically prohibits it.
In short: Find your owner's manual. It's the only way to be certain. Using the wrong oil can damage your engine.
