Cold Weather Whistling: 07 5.3L

[lawfarm]

2007 Yukon SLT, 5.3, 4x4.

If it sits in a cold parking lot all day, on start it has a really loud whistle/whine. It varies speed with engine speed. New accessory belts, tensioners, idlers. Cannot track down to one specific part. Does not change noise when electrical load changes, nor when steering is turned, nor when ac is cycled.

Once it warms up a bit, sound goes away, until you stop at a light and then slowly accelerate away. Then, it whistle/whines again--the pitch starts going up with engine speed but then drops pitch around 1500rpm and then starts going up again, until the truck shifts, then repeats. Does not seem to relate to gear or transmission.

Too loud for a vacuum leak--on a cold start, its LOUD.

Also, if I drive out of my heated garage into the extreme cold, after 10 minutes or so, it will start making the noise on light throttle acceleration as noted above (even though it doesn't start with the noise).

 

[denalianyone]

May be a bad alternator. Disconnect the charging wire for the alternator n see if the whine stops.


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[NGAneer]

Idle air control would be my guess, but not after warming up. Changing with RPM and in the cold makes be think you should check your belts and idlers. Cheap fix to try out to see if its your noise.

 

[TypeRod]

2007 Yukon SLT, 5.3, 4x4.

If it sits in a cold parking lot all day, on start it has a really loud whistle/whine. It varies speed with engine speed. New accessory belts, tensioners, idlers. Cannot track down to one specific part. Does not change noise when electrical load changes, nor when steering is turned, nor when ac is cycled.

Once it warms up a bit, sound goes away, until you stop at a light and then slowly accelerate away. Then, it whistle/whines again--the pitch starts going up with engine speed but then drops pitch around 1500rpm and then starts going up again, until the truck shifts, then repeats. Does not seem to relate to gear or transmission.

Too loud for a vacuum leak--on a cold start, its LOUD.

Also, if I drive out of my heated garage into the extreme cold, after 10 minutes or so, it will start making the noise on light throttle acceleration as noted above (even though it doesn't start with the noise).

Hi Lawfarm, did you ever find the root cause? I think I am experiencing the same issue as well. Its a hard noise to track down bc it seems its coming from everywhere lol

 

[sleuthsnoopy]

I know this is an old thread but I really hate it when people don’t follow up with solutions to their problems..

Well I have the same exact thing happening to my truck..spent months researching and diagnosing and replacing..nothing worked…I saw this thread then another on a Silverado site…coupled with Amazon negative reviews on a part and I can say with certainty that the
AC belt tensioner—AC Delco


Thanks and Yay!!!