Strange High Pitch Noise

papapump51 · May 2, 2008

Hey guys been a while since I have been on - I was out of the country for a bit -

2007 GMC 5.3 Z71 4X4 Crew CAb - So this Am driving to work on the express way and just out of the blue I hit the gas to get going some more ( already cruiseing at a bout 65) so to maintain hit the gas - then I hear like a high pitch wheezing. It is an odd noise and thats all the way I can describe it - Im at work so can not lift the hood yet - But seems like no lose of power almost sounds like someone is turning on a shop Vac under the hood. I have never heard this noise in my truck before - slowed down to about 35 for city street and it is not as loud as it was on the highway at 65ish - so I get in the parking lot and park the truck - hit the gas a few times with my head out the window and i do not hear anythign that seems odd.

So it seems it is there while under load and I wonder if it has anything to do with Im at the lower end of the gas gauge, I am in the bottom half of a quater tank - IDK just thought it was weird that this came out of the blue.

If it does it on the way home guess it is off to the dealer on Monday...and get the rental car....

Any Ideas????? thanks guys and it is good to be back - I have some vacation pictures to share here once i get them uploaded...

Trav_13 · May 2, 2008

Hey guys been a while since I have been on - I was out of the country for a bit -

2007 GMC 5.3 Z71 4X4 Crew CAb - So this Am driving to work on the express way and just out of the blue I hit the gas to get going some more ( already cruiseing at a bout 65) so to maintain hit the gas - then I hear like a high pitch wheezing. It is an odd noise and thats all the way I can describe it - Im at work so can not lift the hood yet - But seems like no lose of power almost sounds like someone is turning on a shop Vac under the hood. I have never heard this noise in my truck before - slowed down to about 35 for city street and it is not as loud as it was on the highway at 65ish - so I get in the parking lot and park the truck - hit the gas a few times with my head out the window and i do not hear anythign that seems odd.

So it seems it is there while under load and I wonder if it has anything to do with Im at the lower end of the gas gauge, I am in the bottom half of a quater tank - IDK just thought it was weird that this came out of the blue.

If it does it on the way home guess it is off to the dealer on Monday...and get the rental car....

Any Ideas????? thanks guys and it is good to be back - I have some vacation pictures to share here once i get them uploaded...

Sounds like the High Pitched Whine from the Power Steering Pump....if you do a search on here you should find some info....its pretty common on the NBS and they are still working on a fix for it. Mine does the same thing, I've just never heard it at 65 or so....but if that is it...there still isn't a fix for it at this time.

papapump51 · May 2, 2008

Thats what I was thinking - but since i was at work didnt have alot of time to search so ... Tray you and have the same rig but mine is the ext cab - same grill and all - Love the white - Like I said I will look under the hood when I get home and listen around and thats that - If it gets worse I will head to the dealer Monday or so -

Guess til they get a fix i bear it - NO cel was thrown or anything

did i describe the noise well enough that you think it is the pump? I mean it really sounds like someone fired up a shop vac

Trav_13 · May 2, 2008

Thats what I was thinking - but since i was at work didnt have alot of time to search so ... Tray you and have the same rig but mine is the ext cab - same grill and all - Love the white - Like I said I will look under the hood when I get home and listen around and thats that - If it gets worse I will head to the dealer Monday or so -

Guess til they get a fix i bear it - NO cel was thrown or anything

did i describe the noise well enough that you think it is the pump? I mean it really sounds like someone fired up a shop vac

Thanks for the compliment on the truck...mine is actually an Extended Cab also....

As far as the noises, just given the way you described it, it kinda makes me think its the pump....

Does it make this noise when its idle and you rev it up, and if so does it get quiter when the RPM's get higher?

I think the bulliten said it could be best heard when the truck is warm and windows up, with the radio turned down, and the A/C off?? Just going by memory, I don't work at the dealer anymore so I don't have access to Dealerworld, otherwise I'd pull up the bulliten for you.

Trav_13 · May 2, 2008

Thats what I was thinking - but since i was at work didnt have alot of time to search so ... Tray you and have the same rig but mine is the ext cab - same grill and all - Love the white - Like I said I will look under the hood when I get home and listen around and thats that - If it gets worse I will head to the dealer Monday or so -

Guess til they get a fix i bear it - NO cel was thrown or anything

did i describe the noise well enough that you think it is the pump? I mean it really sounds like someone fired up a shop vac

Thanks for the compliment on the truck...mine is actually an Extended Cab also....

As far as the noises, just given the way you described it, it kinda makes me think its the pump....

Does it make this noise when its idle and you rev it up, and if so does it get quiter when the RPM's get higher?

I think the bulliten said it could be best heard when the truck is warm and windows up, with the radio turned down, and the A/C off?? Just going by memory, I don't work at the dealer anymore so I don't have access to Dealerworld, otherwise I'd pull up the bulliten for you.

papapump51 · May 2, 2008

yeah windows up - AC off radio down - thats when I heard it most ;) then when i got in the lot and put it in park and hit the gas a few times I didnt hear it outside the cab - guess Ill just keep an eye on it and go from there...GMC and my Warranty are not going anywhere...even though GM posted a 3.3 billion loss...

Trav_13 · May 2, 2008

yeah windows up - AC off radio down - thats when I heard it most ;) then when i got in the lot and put it in park and hit the gas a few times I didnt hear it outside the cab - guess Ill just keep an eye on it and go from there...GMC and my Warranty are not going anywhere...even though GM posted a 3.3 billion loss...

Yeah thats the problem you got then...I've been dealing with mine for over a year now, more than likely you'll probably just get used to it, and be reminded of it every now and then.....I think the original fix was to flush the PS system and then add synthetic power steering fluid which didn't fix it, and some guys reported it made the problem worse....

papapump51 · May 2, 2008

SOunds good - like I said if it becomes worse or whatever then ill goto GMC they are right by my house - thanks for the help!

bgrif005 · May 2, 2008

i have the same thing. give it some gas and its starts whistling with a slight rythmic chirp/whistle. I can even hear it if i am next to a gaurd rail w/ the windows rolled down and i gas it.

really getting tired of this noise to be honest. just seems to get a little louder and more obnoxious each month. i took it to the dealer a few months ago they told me "characteristic of pump" on the invoice. I am getting so sick of GM and the poor quality I am driving...

bgrif005 · May 22, 2008

i need to bring this up again to ask a question about this. i am taking the truck in for some maintenance next week i want to know if this is still the PS pump.

Would the engine under load make the PS pump have a louder whistle? Like Jason said in PARK you cannot hear the same whistle as you do under acceleration. I do here a very very slight whistle in park reving the engine with the windows up and everything off - i do not hear anything outside of the truck with the windows down. But, under load and acceleration the whistle is loud and noticable - especially next to something that will bounce the sound back to you (ie guard rail).

So like I said does the engine under load make a difference on the volume and severity? Seems to me that it wouldn't matter since the PS pump is operating off the serp belt.

05SBZ71 · May 23, 2008

I have a 05 Silverado and had the same problem about a year ago. My service department tried replacing steering ring gears first, they tried that on two occasions and had no success. Finally, the dove into the power steering pump some more and found that one of its gaskets was loose/leaking (something along those lines) and was allowing air in. They ended up just replacing the whole pump. Not sure if thats the case with yours being a NBS truck, but that was just my experience with the high pitch whine.