Superblue has started doing this of late, and at first I assumed it was an old/loose belt (there are two, btw?). Her belts were replaced by NTB after doing something similar about 3 years/15K or so miles ago (which the tech told me turned out to be a PITA, btw ). I’m wondering if one of the belts might just need tightening or r/ring again , although I wonder why that issue would come up at this point. Is that about par for the course with belts? I tried spraying belt dressing on them and that seemed to work at first, but only for 3 or 4 days or so. Last night I sprayed some more on them and the squeal/squall was still there on startup.
Before everyone jumps on the harmonic balancer bandwagon (which I don’t think is the issue), I would point out that USUALLY it only happens on first start of the day (or after the car has been sitting for many hours). The biggest clue though is that as soon as I heard the (secondary) air pump kick in, the sound disappears and everything appears normal. Or maybe the pump kicks in as soon as the squealing stops ? Again, does this sound like a loose belt or one in need of replacement? I’m wondering if the secondary pump has an electric clutch that needs to kick in, and, if so, maybe the clutch is wearing out ? When the belt(s) went out 3 years ago, it was similar, but eventually the squealing continued even while driving (even caught the attention of the local constabulary who pulled me over to give me a ticket for expired plates. )