I'm not sure how you would describe the ticking...
...but perhaps you loosened up the grime around a well-worn belt tensioner shock bushing that is now announcing itself? Usually in that case, the ticking goes away when the motor is revved up. More wear, and the ticking becomes a clanking!
The shock bushing (and associated tensioner) resides just below the radiator hose and in front of the coolant pump...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car