If you need to check drive pulleys to see if they’re out of alignment, one way to do it is to use the Gates Drive Align laser alignment tool. It can show you if the drive pulleys are offset or angled with respect to each other.
Gates’ tool uses a 650nm (red) laser diode powered by a replaceable lithium battery which provides 20 hours of continuous use. It can be used on all automotive serpentine belt drives with four or more ribs.
The Drive Align Laser includes glasses that help you see the laser better, a bungee cord to secure the laser tool to the pulley, and an Allen wrench to align the light beam. The tool comes in a high-impact plastic carrying with space for the other accessories. Overall the Laser Drive Alignment Tool will run you at least $125.