john- oh i see. there was a TSB for the engine cooling system where some loose sealant rattles. does the noise stop when your a/c is off? if so does not apply.
here is the link:
Tsb: 2007-2009 nissan z; tapping noise from dash area when engine is running
IF YOU CONFIRM
A tapping noise coming from the dash area when the engine is running at operating
temperature,
NOTE: This tapping noise, if it should occur, sounds like a screwdriver being tapped on
the work bench. The tapping speed increases and decrease with the engine RPM and
may require engine RPM of about 3000 for the noise to be heard.
DETERMINE IF
The noise is coming from inside the heater core (see Service Procedure).
ACTION
“Back-Flush” the heater core to remove gray silicone debris.