According to RepairPal, the most common cause of a Mini Cooper engine making a ticking noise is low oil level or pressure, an issue with the ignition system, or an exhaust leak.
In most instances, low oil level or pressure or an issue with the ignition system are the culprits, but there is the potential for a ticking noise to be unrelated to any of these issues. If you’re unsure what the root of the ticking noise is, call your local Mini dealership or schedule an appointment with a mechanic to have it diagnosed.