Your 2002 Jeep Liberty Sport's owner's manual is the definitive source for the recommended oil viscosity. However, in general, for a 2002 Jeep Liberty Sport,
5W-30 is usually the preferred oil weight, especially in moderate to colder climates. 10W-30 might be acceptable in warmer climates, but 5W-30 offers better cold-weather performance.
Always check your owner's manual first. The manual will specify the recommended oil viscosity and type (conventional, synthetic blend, or full synthetic). Using the wrong oil weight or type can damage your engine.
