* The specific make and model of the vehicle: Different manufacturers have different recommendations. Consult your owner's manual for the most accurate guidance. This is the most important factor.
* Your climate: Thicker oils (higher numbers like 20W-50) are better for hotter climates, while thinner oils (like 0W-20 or 5W-30) are better for colder climates.
* The engine's condition: If the engine is worn, a slightly thicker oil might help reduce leaks and wear, but too thick an oil can increase stress on the engine.
Generally speaking, for a high-mileage 5.0L engine, a 5W-30 or 10W-30 is a good starting point. These are fairly common weights and offer a balance of protection and flow in a wide range of temperatures. However, always check your owner's manual first. It will specify the recommended oil viscosity grades.
If your manual suggests a different weight, or if you're experiencing unusual wear or leaks, you might consider consulting a mechanic to determine the best oil for your specific situation. They may also recommend a high-mileage specific oil which contains additives to help seal and protect worn components.
