Timing chain. But lots of reported problems with the N47 engine and its chain. If the car has made it to this age then it's probably fine (most issues occurred in the first few years of ownership).

Keep reading to find out what a timing chain replacement costs, what kind of help you can expect from your warranty, and what the key differences are between timing chains and timing belts. Luckily, ...

When should the timing belt on a 2015 BMW 320d with 77,000 miles on the clock have the tensioner checked annually and adjusted?