Probably
Engine tappets
that means you need more oil. it could also be a sticky lifter or slightly bent push rod or even the tappets out of adjustment
The tappets may need adjustment or replacement, due to wear.
try an engine flush at the next oil change, but it will most probably require replacement hydraulic lifters (tappets)
Engine running hotter then 220 degrees can cause valvetrain noise. Bad fuel can also cause valve noise / PINGING sound. Ignition timing to high / Advanced to far, can also cause engine noise.
A bad harmonic balancer can cause a knocking noise. The harmonic balancer doesn't actually produce the noise, but it can cause the noise in the engine.
cold engine
No
A bad compressor belt can cause a whistling noise while running the air conditioner. A bad engine can also cause this noise.
Perhaps a bug on windshield.
it seems your car engine support gone, needs changing.
If the 1999 Suburban noise is a sort of loud banging noise, the problem could be that the engine have jumped time. Jumping time would cause the noise and jerking in the engine.