Oscillation sound?
 

Hey gang, what do we think this sound is? You have to listen kind of close, but it's an oscillating sound that comes and goes rhythmically. I do have a broken bolt on my water pump pulley so maybe it's that? I'm pretty sure the belts are ok. The car has pretty gnarly lifter tick on start up but that goes away pretty quickly once the engine is under load. This video was taken after a 20 minute drive, car is fully warmed up. You can hear the fans come on towards the end.

1990 with a 1.8 swap using FM's kit. All stock right now except for a Fluidamper harmonic balancer and pretty stiff engine mounts. This is a recently rebuilt head too, stock specs. Car sat for a few years so I'm trying to nail down OEM smooth performance before the turbo goes on.

https://youtube.com/shorts/79lpMYQZZ3U?feature=share