This is now the second time this has happened to me: A newly installed Gates SC belt chirps at start-up (sounding much like the din of cicadas) and the sound eventually fades as the engine warms up. Problem easily solved by replacing belt with a NAPA belt. The NAPA belts appear to be made from a softer compound and the cross-section of the belt seems to be thicker. I just swapped the belts today. After 6 months of startup chirping, I couldn’t stand it anymore.

 

Lance, I suspect you're one of the few people to have changed both pulleys - think it's related to that? At 73k miles, I should start looking for a replacement belt, though I might swap the lower pulley next year.

 

I don’t think so. Both chirping belts were brand new.

 

Mine does it too; only at about 15-20k on the belt, but a few summers for sure.