this car has hydraulic lifters.

As for a clicking noise, there are numerous things that could cause this noise. Timing chain tensioners, lifters, plug wires, coils, injectors, etc.

The thing that concerns me is that you can hear it from inside the car while driving, which means that it is fairly loud indeed. I would still take agarden hose to it and see what you can do yourself to locate the source of the sound.