2004 Yukon XL whistle with belt off

Hi Ive had a problem with my yukon xl with the 5.3L Vortec. It has been making a very high pitched whistle sound that matches rpms. I have replaced the alternator, ac tensioner pulley, and the ac belt. It also makes the sound with the serpentine belt off. I have also sprayed brake cleaner around the intake manifold to no avail. Please leave your suggestions.

Thanks

Fuel trims at engine idle speed will asist in identifying intake leaks. High pitched sounds may be generated when exhaust gasses escape at the exhaust manifold gasket or cracks in the exhaust manifold, etc.

zachreilly0 said:

Hi Ive had a problem with my yukon xl with the 5.3L Vortec. It has been making a very high pitched whistle sound that matches rpms. I have replaced the alternator, ac tensioner pulley, and the ac belt. It also makes the sound with the serpentine belt off. I have also sprayed brake cleaner around the intake manifold to no avail. Please leave your suggestions.

Thanks

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A video would help here. Record video with your phone, moving around the engine bay to get a feel for sound from viewer's perspective. Upload it in YT and post the link.

Otherwise a stethoscope is pretty cheap and effective at pinpointing strange sounds.

here is the video

It does kinda sound like a bearing from an accessory, or something like that? A video from the engine bay may be more helpful. Probably not the belt, but sometimes the belts can start screeching if coolant drip on them (like from a leak or replacing something like a thermostat).

I recently bought a cheap HF stethoscope: our 2013 Town & Country developed a squealing. I had replaced the thermostat a few months ago but didn't remember to remove the belt (huge PIA to do that on those engines.) Anyways, with the stethoscope I did not pick up any noise from any accessories and noise disappeared when I removed the belt and ran it...So a new belt fixed the problem.

Did you ever figure this out? My 2004 Yukon XL has been making the exact same noises and this is the first video I have seen of someone with the same problem.

Fundamntl_Force said:

Did you ever figure this out? My 2004 Yukon XL has been making the exact same noises and this is the first video I have seen of someone with the same problem.

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Have you removed both accessory belts to determine if it persists? Results?

Fundamntl_Force said:

Did you ever figure this out? My 2004 Yukon XL has been making the exact same noises and this is the first video I have seen of someone with the same problem.

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I did not I still have the noise, I would check the ac belt tensioner first before anything in your case though

zachreilly0 said:

Hi Ive had a problem with my yukon xl with the 5.3L Vortec. It has been making a very high pitched whistle sound that matches rpms. I have replaced the alternator, ac tensioner pulley, and the ac belt. It also makes the sound with the serpentine belt off. I have also sprayed brake cleaner around the intake manifold to no avail. Please leave your suggestions.

Thanks

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I have the same problem. Thinking it's an intake problem or maybe an idler pulley or belt? I replaced both my belts from O'Reilly's and got the Gates belts when I changed last year?