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Discussion Starter #1
I have a 2002 Yukon Denali that has developed a definite whistling sound while running. Took it in today thinking it was the Serpentine tensioner I had replaced in July but no! They cleaned the Throttle body and checked all vacuum lines to no avail! Oddly enough when it was in the heated shop the noise would not reproduce! They had to take out and drive in the cold air and it started again! Does it at idle and when driving in gear and in neutral. Got charged $116.00 for diagnostics but still have problem. Said I need to bring back for further testing and thier best guess it is the intake gasket! The "guess" would cost $540.00 They would check Map Sensor 1st. and smoke test as well! there wasn't enough time because of closing at Sat. Noon today! Any thoughts? This was at a Chevy dealer but it is a bit discerning that it is such a guessing game! They said it's like exploratory open heart surgery! :eek2: Thanks! :banghead:
 

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Discussion Starter #3
Good start! Thanks!

I saw a video where the guy used a cigar "cough" and blew into hose. Re-torquing I will suggest as I can't do any testing myself right now! I'm going to take to a different dealer Tuesday. I took it today because they had installed the tensioner and serpt. belt and I thought that was the culprit! Also the fact that it was under warranty! Very cold right now! :eek3:
 

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I Googled "2002 Yukon Denali whistling sound running in cold air"

here are some results

http://www.silveradosierra.com/vortec-5-3l-v8/whistling-hissing-noise-t14749.html

http://www.tahoeyukonforum.com/threads/whistle-sound-with-slight-throttle-just-after-applying-throttle.7229/

http://www.gm-trucks.com/forums/topic/37081-whining-noise-front-of-engine/



a lot of the troubleshooting seems to point to Power Steering pumps, especially if you live in the north... (cough cough)

you should be charging the dealer for having to educate their mechanics! I'd say my time & labor is worth about ......$116?
 

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the PS pump is probly the whine..
but the whistle sounds like vacuum leak..
and
winter time the air is denser so the IAC valve is closed more, maybe that is the whistle, as said?? :dontknow:

you would think there should be at least one mechanic with a stethoscope
or even one of those fancy noise finding microphone thingamabobs..
get a piece of heater hose and find where its coming from first..

:texas:
 

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Discussion Starter #6
No whine not P.S.

A true whistle...I will check out other links and ideas! Is it harmful to drive like this??? I will let you know what it was! Thanks all! :bigups:
 

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Discussion Starter #7
Thanks!

I did the same and looked at these and many more! This vid is the closet to the tea kettle sound mine is making! Hopefully not a cracked intake! :shocked:
https://youtu.be/Y5_m6LRqkAw

I Googled "2002 Yukon Denali whistling sound running in cold air"

here are some results

http://www.silveradosierra.com/vortec-5-3l-v8/whistling-hissing-noise-t14749.html

http://www.tahoeyukonforum.com/threads/whistle-sound-with-slight-throttle-just-after-applying-throttle.7229/

http://www.gm-trucks.com/forums/topic/37081-whining-noise-front-of-engine/



a lot of the troubleshooting seems to point to Power Steering pumps, especially if you live in the north... (cough cough)

you should be charging the dealer for having to educate their mechanics! I'd say my time & labor is worth about ......$116?
 

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Discussion Starter #9
Good to know! Thanks!

Right now the only thing that is noticeable is the whistling sound! And sometimes you can find a sweet spot when driving that it goes away! No missing or hesitation from engine and idles perfectly! I will take all the gained info. from here along with me and let them now at the new dealer! ILYK! Thanks again! :wink1:

if it is a vacuum leak? a small one is not harmful, the computer can compensate for it..
if it gets bad enuff that the idle speed starts going up on its own, then youll have to do something..

:texas:
 

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sweet spot when driving? certain RPM or mph? what about certain speed at certain RPM in certain gear? it may all balance out at that point. try manual shifting and see if you can get consistent results.
 

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Discussion Starter #11
What would that point to?

Will do! I believe it was at 1500RPM's in drive. I will try the others next time I go out! ;-)

sweet spot when driving? certain RPM or mph? what about certain speed at certain RPM in certain gear? it may all balance out at that point. try manual shifting and see if you can get consistent results.
 

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If it's under warranty let them figure it out it's in the price you paid for the car. Why would they charge you for looking at it if they heard the noise???? I haven't had a car under warranty for 30 years so I don't really know what's covered anymore???:cali:
 

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Discussion Starter #14
Nope!

I wish! It's a 2002 Yukon Denali with grey leather int. and a 124K. miles on the clock! :bigups: I just recently put the Avalanche 20" rims with new Cooper tires on it!


If it's under warranty let them figure it out it's in the price you paid for the car. Why would they charge you for looking at it if they heard the noise???? I haven't had a car under warranty for 30 years so I don't really know what's covered anymore???:cali:
 

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They tried something like that but said the way the manifold mounts that you can't get under to access all the spots it may be leaking at? :dontknow: I'm taking it to a different mech. tomorrow...hopefully with better results! ILYK! Thanks!

If it's temp sensitive it could be a leak at the manifold.
You could try the propane method works some times
 

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no smoke test yet?? stethoscope, microphone??

the problem with the propane or carb spray test is that the computer will compensate for the
increase in idle speed your looking for, them computers are quick..

if they find a small leak that's accessible?? have them show it to you..
you could try cleaning it real good, and a smear of RTV or Urethane sealer..
you may have to wait till summer to do it, but might save you a 1000$ by the time its done..

:texas:
 

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Discussion Starter #17
O.K!

I'm taking it in tomorrow so if they find something like that I will ask them if they could do that while in the warm shop! The noise is :eek3: to say the least! Thanks!

no smoke test yet?? stethoscope, microphone??

the problem with the propane or carb spray test is that the computer will compensate for the
increase in idle speed your looking for, them computers are quick..

if they find a small leak that's accessible?? have them show it to you..
you could try cleaning it real good, and a smear of RTV or Urethane sealer..
you may have to wait till summer to do it, but might save you a 1000$ by the time its done..

:texas:
 

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If it's the same as the 5.3 there was a design change at some point to the intake gaskets. Had to do with the rubber used in the o rings.in my experience that means the original was not sufficient. Also there are metal sleeves in the plastic intake to help with overtightening and cracking.
 

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Discussion Starter #20
I recall a mention of that...possibly unleaded gas eating away at the gaskets? Soo many possibility's I just hope they find it tomorrow! :beer:

If it's the same as the 5.3 there was a design change at some point to the intake gaskets. Had to do with the rubber used in the o rings.in my experience that means the original was not sufficient. Also there are metal sleeves in the plastic intake to help with overtightening and cracking.
 
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