Could be many, many reasons some as simple as a small stone caught inside a hub cap.
It depends. If it is a loud clicking sound you will want to take it to a professional Immediatly! Without Delay!
The clicking may be the belt tensioner clicking. I know that mine is causeing a clicking noise. If you get a friend to help you, you will be able to see it happen if that is the case.
A clicking sound when you turn the key could mean your battery is dead. It could also indicate the starter is going out.
Have the alternator checked.
Perhaps clutch throw-out bearing?
if you have an electrical fuel pump can sometimes do that
You should check the cv joints on your drive line. When they start to go bad they'll start clicking when you turn.
Weak battery, corroded or loose battery cables, failed starter.
Not much info to go on but it could be the exhaust system heating up or cooling down.
A bad resistor can cause your BCM to make a clicking sound. The clicking noise can be caused by the relays and replacing the BCM will fix the problem.
I will take a stab at the answer....... Do you live in a hot climate? If so, when the engine is hot and possibly a new exhaust was installed, the clicking would be the exhaust cooling off. Sound good ?
When you drive over a clicking bettle.