Lexus recommends replacing the timing belt on the 3.0L engine every 90,000 miles, or every 72 months (6 years).
To save on future repairs or issues, it's a good idea to have the timing belt tensioner and water pump replaced at the same time.
RepairPal Certified shops can diagnose and repair your 2002 Lexus RX300. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.