'01 Tahoe whistling noise *FIXED*

Sounds like there's been lots of other trucks having similar issues but I haven't found a fix on any threads. I've done all I can and even my local mechanic is stumped. Here's what I know;

2001 Tahoe LT 5.3 4x4 w/129k

Already checked airbox and connections

Already cleaned Idle Air Control

Already cleaned Mass Air

Intake gasket done at 115k

Vehicle is not modified in any way

I live in Chicago and have noticed with the cold weather that my truck is whistling at a certain RPM range. The whistle or air noise happens between 1,900 RPMs and 2,200 RPMs like clock work when it's cold. It is not coming from the speakers, and it follows the throttle response perfectly. If it's below 35 degrees and I'm doing 70 MPH (2k RPM), it will just whistle steady till the truck either completely warms up or I let off the throttle.

Spare me your turbo comments please, but it does actually sound like I have the worlds tiniest turbo spooling at 70mph.

Any thoughts would be greatly appreciated-
Brian

belt tensioner or idler pulley bearing. Possibly water pump or alternator bearing.

If you have an automotive stethoscope that helps to check bearings. There is also the ac compressor clutch. You can turn on the compressor to see if the squeal goes away or changes.

have you tried spraying brake clean around your intake track to see if there is a leak? it will cause it to rev up if it has a leak. spray around the throttle body, fuel injectors, where the intake meets the head and where all the vacuum sensors hook into the intake manifold. if it revs up on any of those you have found your leak.

rockola1971 said:

belt tensioner or idler pulley bearing. Possibly water pump or alternator bearing.

Click to expand...

^^^This. Check your belts and pulleys, including the tensioner.

Mine was making the same noise. I know it sounds odd. But, it ended up being the power steering fluid was low

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.......friend of mine has a 2006 Chevy truck. His had a weird whistle sound that he couldn't find for the longest time.

One day, I'm over at his house. We're doing some work on his truck. I'm flushing the coolant system with the engine running. I rev up the engine a few times. And he asks me how I got the truck to stop whistling. I told him it's a secret (In reality, I didn't know).

Turns out the whistling was coming from the little plunger guage thing on the side of the air filter housing........which (the guage) is supposed to give you an idea of how dirty the air filter is (had the filter box off the vehicle so we could clean it out. No box, no filter, no whistle.

Recently I did the water pump, idler pulley and tensioner and new belts at the time. My power steering does the typical 5.3/Tahoe light whining but I don't think that's got anything to do with the whistle I'm getting. I'm intrigued by the air box sensor so I just messed with it a little and we'll see. I also just sprayed down the obvious areas with some brake clean for 3rd time and still no change.

I've had loud belts and loud power steering, this isn't like either. It literally sounds like there is a miniature turbo on the truck.

Please see the video I posted on youtube;

Are you sure that the noise isn't coming out of the tweeters located up near the windshield? A failing alternator can produce noise in the audio system that varies with engine rpm.