No need. If my test doesnt provide any results, next would be remove idler/tensioner pulley. Spin it with your finger in the middle. If it sings and freewheels for a long time, its likely bad. A good bearing wont make a "mmmmmmmmmm" noise at all, and will have a little bit of rolling resistance. It should spin, but not for a super long time. Its difficult to say when its intermittent.
RIP Ben "Jever" Doebele, we wont forget you
Please, call me Chadley
1997 328iS... HR coilovers, Brembo F40 calipers, camber plates, it needs a CUMMINS!!
1990-somethin Chevy K3500... Cummins, cab swap, 5 speed, and lots of motor work. 20 MPG, 40 PSI, 507 ft/lbs torque