[SOLVED] HELP!! Weird flute like whistle coming from engine bay.

[lilsettals]

I have a 2004 GMC Yukon with 267,000 miles on it and recently I had some work done to it during the summer. I recently changed the water pump, thermostat, upper radiator hose, all belts, pulleys, and tensioners, alternator, oil pan, gasket, crankshaft seals, and valve cover gasket. And I noticed that as it started to get colder with that around the low RPM range between 2000 and 1000 RPM my truck expects to make a flute noise for a second and then it will stop and they kept doing it recently, whenever I was in the rpm range. First, it only did him under load until we start to get really cold like in the teens then it started to whistle on idle only in very low temps it’s been a while since it has been in the teens and I have change the PCV hose and the noise is still there, but it does not do it on idle recently when it’s been below 20. I was thinking of changing the valve cover because it cannot change the PCV valve without a new valve cover in the later models can anybody help with diagnosis?Sound <— here’s the video of what it sounds like.

 

[Fless]

Does the pitch rise and fall with rpms?

I'd probably remove the accessory drive belts and run it for a short time to see if it's something in the belt paths.

 

[lilsettals]

Does the pitch rise and fall with rpms?

I'd probably remove the accessory drive belts and run it for a short time to see if it's something in the belt paths.

Yes I does but only in that rpm range 1000-2000. But it doesn’t happen in weather above 45 degrees.

 

[houstontaylor]

Mine turned out to be bearing noise on the air conditioning belt tensioner from Canada. Just like yours it did it only when it was below a certain temperature and at a certain rpm. It did it even on a new one so I suspect they were using a cheaper bearing not suitable for low temperatures possibly. I bought a different brand that was made in India and the noise went away. I guess the Indian one didn't use Chinese parts since they are enemies.

 

[Eighthtry]

If that doesn't work you might add some bass and a steel guitar.

 

[OR VietVet]

Take belt off and run it. You need a mechanic's stethoscope to pinpoint the noise. Pretty loud where the snorkle attaches at the throttle body. Maybe even a bad new water pump.

 

[lilsettals]

Take belt off and run it. You need a mechanic's stethoscope to pinpoint the noise. Pretty loud where the snorkle attaches at the throttle body. Maybe even a bad new water pump.

Update the sound sounds like it’s coming from the low front end of the motor a guy earlier said ac tensioner Sound <——

 

[lilsettals]

Mine turned out to be bearing noise on the air conditioning belt tensioner from Canada. Just like yours it did it only when it was below a certain temperature and at a certain rpm. It did it even on a new one so I suspect they were using a cheaper bearing not suitable for low temperatures possibly. I bought a different brand that was made in India and the noise went away. I guess the Indian one didn't use Chinese parts since they are enemies.

Yeah the sound source is from that areaSound <——

 

[Fless]

I don't hear a thing on the sound clip.

 

[lilsettals]

***UPDATE**** it was the ac tensioner. If you have this problem check your ac tensioner because it’s probably that.