Why is my Nissan Qashqai's engine making a strange noise?

I noticed that my Nissan Qashqai's engine has been making a strange noise recently. It's not a constant noise, but it comes and goes. What could be causing this and should I take it to a mechanic?

It's always a good idea to get any unusual noises in your car checked out by a mechanic. It could be something as simple as a loose belt, but it's better to be safe than sorry.