Replacement Interval: The timing belt on a 2004 Toyota Sienna should be replaced every 90,000 miles or 7 years, whichever comes first.
It's important to follow the recommended replacement interval to avoid potential engine damage. A broken timing belt can cause the pistons to hit the valves, resulting in extensive and expensive engine repairs.
Please be aware that some Sienna models used with the 3.0L 1MZ-FE V6 engine have a timing chain instead of a timing belt. Timing chains typically don't have a specified replacement interval because they are designed to last over the complete lifespan of the car. To be certain, refer to your Owner's Manual for the exact intervals or recommendations specified for your particular Sienna model.
