I have a 2006 Toyota Camry. Has over 200,000 km. tapping noise has started.

Hello, if you have an internal engine tapping noise, this will take a trained ear to make a good assessment on where it is likely originating from, and then a repair process can also be suggested. It could be an upper end valve train noise, or a lower end crankshaft area noise, for example. It's very important to have a trained ear listen for the noise, because it can save you costly unnecessary tear down of components for inspection in some cases.

Possibly a problem within the serpentine drive belt circuit - a failing driven accessory can cause same noise - this includes the *water pump* .. Serpentine drive belt can be removed and engine 'temporarily operated' to determine if noise is external - within the drive belt components. That is the only diy testing recommendation .. Even then - some auto repair skills are required!