Hello all!

2007 Tahoe LTZ has ~ 281K miles on it.

I was in my room getting ready and my wife was leaving for work...I heard her start up the Tahoe and I immediately heard a loud whistling noise coming from the vehicle. I was in the house and heard it through our thin windows, lol. So upon start up it was pretty loud, then it kind of died away, but as soon as she backed out of the driveway I heard it a little more, then when she drove forward and accelerated away, I heard it again and its consistent with vehicle RPM.

Almost two weeks ago, I changed the air filter and removed and cleaned the MAF. I did do a test drive afterwards and did not hear any noise that was out of the ordinary. I will check the air box and MAF and air intake connections when she gets home.

But it def. sounds like air leaking, and its def. a whistle.

I do have the original water pump still in the vehicle. Can a failing water pump or power steering pump or any other accessories along the belt drive make a whistling sound? This is def. not a WHINE, its a WHISTLE.

I just replaced the both main drive belt and a/c belts and all tensioners earlier this year in the spring.

Thanks in advance!

 

I got up this morning and started the vehicle, and the whistling was still there...I popped the hood and tried to narrow down where it was coming from, but it was just soo loud, it was impossible to narrow down. I have some video of it.

I got under the car and had my son rev the engine a few times. It wasn't coming from the exhaust leak that I know I have, which is coming from my Corsa exhaust mid-pipe. While I was under the car, and my son revving the engine, the whistle was coming from my engine bay. As you can see in the video, as the engine was getting warmer, the whistle was stopping only when you rev the engine is when you heard it. I think now that it's an exhaust manifold leak on the passenger side, but I just can't narrow it down for sure.

EDIT: Not sure why the video won't upload...let me work on it

 

I think I found the issue....not sure how the stock OEM GM exhaust manifold it...but is this a crack or is this how it comes from factory?

EDIT: now that I'm looking at the pic, the gasket seems fine?! I don't know, I've exhausted my backyard mechanic troubleshooting. My neighbor suggested a possible vacuum leak...but I don't even know where to start looking for a vacuum leak on any car, lol

 

Nevermind...I think thats normal...here is an OEM exhaust manifold in ebay, I think its the same part number

 

Just an update...tonight I finally caught the culprit of the whistle...the a/c belt tensioner, which I just installed only 6 months ago. I bought it off amazon, but it is genuine GM, not sure how to try and get it replaced under warranty since I did the install myself and not the dealership.

Any suggestions on how to get this part replaced under the parts warranty?