Hello Sean,
by hydro i mean hydraulic lifter. Sorry, some german to english mistranslation.
You can test hydraulic lifters. To do that you have to remove the camshafts first and than have to remove the hydraulic lifters. To do that you'll need some special tools. So this is more for the advanced DIY mechanic.
If you can hear that the noise is coming from the valvetrain, it might be caused by a valve or hydraulic lifter.
But before testing hydraulic lifters i would recommend to go through all easy to do test steps listed above.
If the noise does come from another part of the engine we have to investigate more into that.
At the moment i would recommend to let the engine run as little as possible and don't rev it up.
Regards, Markus