Does anyone know what the whining noise is on the 99 LS1 or maybe even other LS1's? When I start my car there is always this whining kind of noise for about the first 3 mins or so and then it just turns off. I just want to know what it is.

 

If you had done a search you would have found that it's the electric A.I.R. system pump that comes on during a cold start to add air to the cats to help the get up to temp faster. There's many a post about it.

 

and if your engine is warm it's only a few seconds..... yes, this is the pump from the A.I.R. system....

 

I removed mine. Cleaned up the engine bay a bit making plug changes easier. You need to delete it from the cpu also or you will get a SES code.

 

Or it is the tensioner. See the sticky at the top about rebuilding them...