tell me the mileage and i will let you know about the rattle
Loose belts
If your rattling noise is coming from behind the dashboard it may be to do with the heater/fan box, replaced a couple. If the noise is coming from the engine bay, then I`d suggest checking oil level first, if it`s a bit low it can take longer to reach the top of the engine on initial start-up, causing it to rattle. Otherwise, take it to a mechanic who you trust...
the substrate inside is breaking up,your cat-con is shot!!
From what I can tell, the rattle is most likely coming from your alternator, Take It In!
Moisture builds up on the accessory belt and causes it to slip making the sqeeking sound.
The rattle is composed of a series of hollow, interlocked segments made of keratin, which are created by modifying the scales that cover the tip of the tail. The contraction of special "shaker" muscles in the tail causes these segments to vibrate against one another, making the rattling noise (which is amplified because the segments are hollow).The muscles that cause the rattle to shake are some of the fastest known, firing 50 times per second on average, sustained for up to three hours.
Is it a lifter ticking?
The Diff oil ir either needing changed or topped up, if its a whining noise that is.
If it's rear brakes there drums. Mine have made noise since it was new. Only when you first start up. I have a 96
There could be numerous reasons why a Suburban is making engine noise at start up. It could be anything from a blown gasket to a spark plug. A mechanic will be able to find out the cause of the noise.
if it is more of a slapping rattle like metal to metal for every revolution of the motor check your crank pulley... my Zuk was making a similar noise... ended up being the 4 bolts holding the pulley on and sheared them right out of my crank sprocket... it sounds rediculous but trust me its worth checkin out