Every60k-90k miles. If an engine is equipped with a timing belt, the timing belt must be replaced at the service interval specified by the vehicle manufacturer regardless of whether or not any problem is visible, typically in the range of 60,000 to 90,000 miles. Your vehicle owner’s manual should state the specific service interval. Atiming chain will need replaced far less frequently than a timing belt, resulting in a lower cost to maintain your 2009 Audi A4 for the owner. Benefits of Timing Chain Replacement While a timing chain will usually last far longer than a timing belt, it will suffer from wear and tear and will need replaced at some point during the life cycle zBdC1m.