# Chirping under hood,,, with video.



## Pruittx2 (Mar 24, 2012)

Not sure,, if it's a belt,,, possibly alternator or what,,, just thought I'd put this out there to see if anyone else has heard this 20011 RS auto 99500 miles.

https://youtu.be/CYyWeXYWWwM


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## Robby (Mar 1, 2013)

Remove dipstick while to is making this sound……write back with findings...

Rob


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## Pruittx2 (Mar 24, 2012)

no change. But inform me as to what I'm looking for with that? Just wondering,,, I'm a car guy,, and know my way around under the hood,,, but haven't had to with this car,,, the wife loves it.


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## Robby (Mar 1, 2013)

Pruittx2 said:


> no change. But inform me as to what I'm looking for with that? Just wondering,,, I'm a car guy,, and know my way around under the hood,,, but haven't had to with this car,,, the wife loves it.


There have been several cases of a relief valve, built into the intake manifold, sticking wide open.
When it does so, the crankcase pressurizes…..the valve shuts off the pcv and the vent hose from the valve cover.
The pressure overwhelms the harmonic balancer seal lips and it chirps like a bird….a very similar sound to your video.

There have been several cases though, of the seal lips drying out and causing the chirping as well.
Pulling the dipstick, to relieve pressure if there is any, is the first step in the diagnostic tree.

Before you go much further, does the sound change A/C on A/C off? Many compressor idler bearing failures were occurring in the early years and compressor replacement was required…..there are no service parts unless something changed in the last year or two……these made a chirping sound as well…..but not when the compressor was energized.

Rob


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## ChevyGuy (Dec 13, 2014)

Pruittx2 said:


> I'm a car guy,, and know my way around under the hood,,, but haven't had to with this car,,, the wife loves it.


Among the possible causes of chirp are loose sparkplugs. It might be worth re-torquing them.


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## jblackburn (Apr 14, 2012)

That sounds like your serpentine tensioner


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## spaycace (Feb 9, 2012)

And just to be sure ... while you're at it, make sure there's not a bird nest in there somewhere! :idiot: LOL


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## Mo Cruze (Aug 29, 2014)

Robby said:


> There have been several cases of a relief valve, built into the intake manifold, sticking wide open.
> When it does so, the crankcase pressurizes…..the valve shuts off the pcv and the vent hose from the valve cover.
> The pressure overwhelms the harmonic balancer seal lips and it chirps like a bird….a very similar sound to your video.
> 
> ...


This happened to me. at least now people know what to look for. Dealer had my car on and off for 3 weeks before they figured it out...


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## Pruittx2 (Mar 24, 2012)

Ok,,, that's for all the help guys,,, Yesterday,,, on the drive home,,, the wife said, it bucked pretty hard on 2 different occasions. with 99541 on the clock,,, I told her take it to the dealership, and I'll meet you there. Just got off the phone with them, and yes indeed the # 2 plug was loose causing the noise,,, also code for # 2 and 4 missing is a bad coil pack on that bank. The coil pack USED to me covered,, but GM made a change and it's not any more. The GM replacement IS lifetime warranty. So $370 for 4 new plugs, 1 new coil pack,, and I told them to do a trans fluid change per GM recommendations also. <--= $160 for that. I ask about trans filter,, they said GM recommends every other fluid change on the filter. So Filter @ 200,000 miles.


Thanks again,, for a wonderful community and all the help. Happy Cruz'n


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## Robby (Mar 1, 2013)

Pruittx2 said:


> Ok,,, that's for all the help guys,,, Yesterday,,, on the drive home,,, the wife said, it bucked pretty hard on 2 different occasions. with 99541 on the clock,,, I told her take it to the dealership, and I'll meet you there. Just got off the phone with them, and yes indeed the # 2 plug was loose causing the noise,,, also code for # 2 and 4 missing is a bad coil pack on that bank. The coil pack USED to me covered,, but GM made a change and it's not any more. The GM replacement IS lifetime warranty. So $370 for 4 new plugs, 1 new coil pack,, and I told them to do a trans fluid change per GM recommendations also. <--= $160 for that. I ask about trans filter,, they said GM recommends every other fluid change on the filter. So Filter @ 200,000 miles.
> 
> 
> Thanks again,, for a wonderful community and all the help. Happy Cruz'n


Well alrighty then……except for the trans filter info……it is only replaceable by pulling/disassembling the trans……not a service item, it is life of car (trans) item.

Rob


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## Pruittx2 (Mar 24, 2012)

Tranny filter info, provided by chick at dealership. Good to know thanks,,, Sounds kinda like the fuel filter,,,, on the pump in the tank. Picked it up a while ago,,,, wife say's all seems good. So a reset of the Average MPG,,, to see what the new plugs get me. been sitting around 32 for months. She drives 90 miles a day M-F Bill was $529 out the door,,, low fuel like just came on when she dropped it. But when we picked it up,, it said range 171miles. So I think they put so gas in it! lol but don't see it on the bill.


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