Dirt on a belt can cause a ticking sound as the belt articulates on/off of the pulleys. I agree with PaulJ2, you can remove the belt and run the engine.
Or use my friend's technique. He's a 30+ year high-line import mechanic (MB, BMW, etc). He sprays a little silicone spray lube on the offending belt.
I've seen him do it on my Tiger's serpentine belt. The ticking noise went away _instantly_. It's just a diagnostic tool, it won't eliminate the noise for long. But it does no harm (I've run that same belt another 55,000 miles). Now if it's belt noise, you'll know and can decide if it's annoying enough to be worth replacing.
Jim, "Mo' coffee!"
