Does the Ford Fiesta ST have a timing belt or chain?

I'm sorry to disappoint You, but the Ford Fiesta ST uses a timing belt, not a timing chain. You should look into replacing the timing belt around every 60,000 to 90,000 miles, though Ford recommends slightly different values depending on the model year and trim. If You go by years rather than miles, it's usually 7 to 10 before You need to worry about it. Some signs Your timing belt may be starting to fail are a ticking noise coming from the engine, or it not turning over. You may also notice an oil leak near the motor, or that when revving Your engine, it sounds unusual. At between $500 to $900 to replace, this is one item where doing it Yourself often makes a lot of sense, if it's time to have it replaced.