Strange rattling sound when under light load. - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

S3XPanther · 04-01-2012, 08:37 PM

My 2012 SS L99 (just broke 1000mi a few days ago) has of late developed a strange noise. When in either drive or reverse, and while feathering the throttle, I hear a rattle that would seem to be coming from directly under the cabin. My original inclination was to attribute the noise to the exhaust, however, when revving in park I cannot duplicate the noise. In addition, the noise is only evident when the car has really warmed up and has been running for at least 20min. This is why I believed it to be exhaust related; possibly an improperly torqued clamp expanding from warm up and causing the pipes to move around a bit more.

I know there is a TSB on an exhaust rattle, but again this doesn't happen when not under load; so I therefore assumed it couldn't be the exhaust.

So I'm stumped. Am I mistaken in believing that it isn't the exhaust? Or is the issue something else entirely?

Thank you.

S3XPanther · 04-02-2012, 12:09 AM

Never mind. I just read up on exhaust pressures under load and free revving. I'm an idiot.

Guess it is the same problem stated in the TSB.

*TAG UR IT* · 04-02-2012, 12:42 AM

I had a rattle that progressively got worse directly under the cabin. Happened only between 15 to 20 mph (or so). Not with the clutch in stopped revving. Only between those speeds.

Turned out my center bearing in the drive shaft went out. Had to replace the entire thing drive shaft. FYI.

S3XPanther · 04-02-2012, 12:59 AM

Damn that's scary. Do you honestly think that could happen with a car with just over 1000mi? In may case, I'm getting a faint rattle at about 5mph and only when warmed up. Either way, a trip to the dealer is a good idea I guess.

OBSSEST · 04-02-2012, 05:12 PM

You may also be hearing the AFM kick into 4 cyl. mode. When you blip the throttle, it turns off and goes back to 8 cyl. AFM makes our L99's vibrate and rattle. Sadly enough, this is normal operation and the only fix is to have AFM turned OFF via a tune. In which case, you risk that your powertrain warranty is void.

S3XPanther · 04-02-2012, 05:47 PM

Quote:

Originally Posted by OBSSEST

You may also be hearing the AFM kick into 4 cyl. mode. When you blip the throttle, it turns off and goes back to 8 cyl. AFM makes our L99's vibrate and rattle. Sadly enough, this is normal operation and the only fix is to have AFM turned OFF via a tune. In which case, you risk that your powertrain warranty is void.

No I know what the AFM sounds like, this is actually my 2nd SS. This happens at a crawl.

S3XPanther · 04-02-2012, 06:04 PM

Tell you what, I'll attempt to shoot a video sometime this week.

S3XPanther · 04-02-2012, 06:11 PM

Ok guys, check this out. Found a video which contains a similar if not identical noise I'm experiencing. According to the user, the issue was a bad gasket that caused the O2 sensor to fit improperly. Forward to about 0:17. Anyway, here it is:

kraut1971 · 09-12-2015, 10:13 AM

Bump - Am experiencing the same annoying rattle while driving between 25-30 MPH.

It this something that justifies a warranty claim???

Rock-It Man · 09-12-2015, 05:21 PM

The L99 is never on 4 cylinders when idling out of gear.

Rattling could be any of the many heat shields or something in the drivetrain.

I have a rattle when passing through about 2500 rpm under light load. But it's hard to duplicate, so far. Sounds like sheet metal like a heat shield, but you never know. Rattles can be very hard to characterize.

JohnBrain · 06-14-2016, 02:21 PM

Since day one I received the car there was a rattle but only from about 30 to 40mph coasting so not engine rev related. Noise is there in gear or neutral. Have been several times to the dealer and they tray each time but comes back. Now have to have a regional tech come out to look at it. Hope I can get it to make the rattle since it sometimes goes away.
Anyone else have this same issue might need support to argue warranty.

Quicksilver-SS · 08-18-2016, 06:14 PM

Took mine in for it's last free oil change and had them look for the rattle on my M6 SS.
They said it was Gear Rattle and common on manual cars and trucks. They gave me of copy of TSB 03-07-004K And it describe the low speed, light load rattle I am hearing.

https://www.google.com/url?sa=t&rct=...zTC5i4Sfs7JHpw

Jayjellyfish212 · 08-19-2016, 04:29 PM

Mine has a light rattle on warm up and only when I'm clutching the car In drive. Seems to be in far back area of trunk. Goes away once clutch is completely let out and slight gas is given. Don't last long and seems to be only at warm up. I'm thinking might be loose exhaust part or heat shield and once hot it's tight again.

HyperV117 · 08-19-2016, 04:41 PM

That video sounded like a loose heat shield.

04-01-2012, 08:37 PM	#1
S3XPanther by Odeon Drives: '12 SS/RS A6 IOM SOLD, '13 1LE IOM Join Date: Nov 2011 Location: Good question Posts: 1,707	Strange rattling sound when under light load. My 2012 SS L99 (just broke 1000mi a few days ago) has of late developed a strange noise. When in either drive or reverse, and while feathering the throttle, I hear a rattle that would seem to be coming from directly under the cabin. My original inclination was to attribute the noise to the exhaust, however, when revving in park I cannot duplicate the noise. In addition, the noise is only evident when the car has really warmed up and has been running for at least 20min. This is why I believed it to be exhaust related; possibly an improperly torqued clamp expanding from warm up and causing the pipes to move around a bit more. I know there is a TSB on an exhaust rattle, but again this doesn't happen when not under load; so I therefore assumed it couldn't be the exhaust. So I'm stumped. Am I mistaken in believing that it isn't the exhaust? Or is the issue something else entirely? Thank you. __________________ "It works 60% of the time, every time." "Some say it's a waste of time, others say it's an incredible waste of time." "The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." 2013 IOM SS/RS - 1LE. Born 5/6/2013 (1 of 32 1SS IOM 1LE's)

04-02-2012, 12:09 AM	#2
S3XPanther by Odeon Drives: '12 SS/RS A6 IOM SOLD, '13 1LE IOM Join Date: Nov 2011 Location: Good question Posts: 1,707	Never mind. I just read up on exhaust pressures under load and free revving. I'm an idiot. Guess it is the same problem stated in the TSB. __________________ "It works 60% of the time, every time." "Some say it's a waste of time, others say it's an incredible waste of time." "The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." 2013 IOM SS/RS - 1LE. Born 5/6/2013 (1 of 32 1SS IOM 1LE's)

04-02-2012, 12:59 AM	#4
S3XPanther by Odeon Drives: '12 SS/RS A6 IOM SOLD, '13 1LE IOM Join Date: Nov 2011 Location: Good question Posts: 1,707	Damn that's scary. Do you honestly think that could happen with a car with just over 1000mi? In may case, I'm getting a faint rattle at about 5mph and only when warmed up. Either way, a trip to the dealer is a good idea I guess. __________________ "It works 60% of the time, every time." "Some say it's a waste of time, others say it's an incredible waste of time." "The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." 2013 IOM SS/RS - 1LE. Born 5/6/2013 (1 of 32 1SS IOM 1LE's)

04-02-2012, 06:04 PM	#7
S3XPanther by Odeon Drives: '12 SS/RS A6 IOM SOLD, '13 1LE IOM Join Date: Nov 2011 Location: Good question Posts: 1,707	Tell you what, I'll attempt to shoot a video sometime this week. __________________ "It works 60% of the time, every time." "Some say it's a waste of time, others say it's an incredible waste of time." "The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." 2013 IOM SS/RS - 1LE. Born 5/6/2013 (1 of 32 1SS IOM 1LE's)

09-12-2015, 10:13 AM	#9
kraut1971 BITCHN Camaro Drives: SOLD! Back in the looking zone... Join Date: Feb 2015 Location: Saline, MI Posts: 248 View My Garage	Bump - Am experiencing the same annoying rattle while driving between 25-30 MPH. It this something that justifies a warranty claim??? __________________ BITCHN

04-02-2012, 12:42 AM	#3
TAG UR IT www.Camaro5store.com Drives: 2014 ZL1 #705 Join Date: Jul 2006 Location: SA, Texas Posts: 26,558 View My Garage	I had a rattle that progressively got worse directly under the cabin. Happened only between 15 to 20 mph (or so). Not with the clutch in stopped revving. Only between those speeds. Turned out my center bearing in the drive shaft went out. Had to replace the entire thing drive shaft. FYI.

04-02-2012, 05:12 PM	#5
OBSSEST Drives: 2010 Camaro 2SS RS, Black Join Date: Sep 2009 Location: Sacramento Posts: 413	You may also be hearing the AFM kick into 4 cyl. mode. When you blip the throttle, it turns off and goes back to 8 cyl. AFM makes our L99's vibrate and rattle. Sadly enough, this is normal operation and the only fix is to have AFM turned OFF via a tune. In which case, you risk that your powertrain warranty is void.

09-12-2015, 05:21 PM	#10
Rock-It Man 376 cubic inches of fun Drives: 2023 Camaro ZL1 A10 Join Date: Jul 2010 Location: MA Posts: 4,033 View My Garage	The L99 is never on 4 cylinders when idling out of gear. Rattling could be any of the many heat shields or something in the drivetrain. I have a rattle when passing through about 2500 rpm under light load. But it's hard to duplicate, so far. Sounds like sheet metal like a heat shield, but you never know. Rattles can be very hard to characterize.

06-14-2016, 02:21 PM	#11
JohnBrain Drives: Hot Wheels SS Conv Join Date: Oct 2014 Location: NJ Posts: 1	Heat Shield Rattle Since day one I received the car there was a rattle but only from about 30 to 40mph coasting so not engine rev related. Noise is there in gear or neutral. Have been several times to the dealer and they tray each time but comes back. Now have to have a regional tech come out to look at it. Hope I can get it to make the rattle since it sometimes goes away. Anyone else have this same issue might need support to argue warranty.

08-18-2016, 06:14 PM	#12
Quicksilver-SS Drives: 2014 1SS / RS M6 Join Date: Dec 2014 Location: Zebulon, NC Posts: 602	Took mine in for it's last free oil change and had them look for the rattle on my M6 SS. They said it was Gear Rattle and common on manual cars and trucks. They gave me of copy of TSB 03-07-004K And it describe the low speed, light load rattle I am hearing. https://www.google.com/url?sa=t&rct=...zTC5i4Sfs7JHpw

08-19-2016, 04:29 PM	#13
Jayjellyfish212 Drives: 2014 1LE Join Date: Aug 2015 Location: Upstate NY Posts: 2,050 View My Garage	Mine has a light rattle on warm up and only when I'm clutching the car In drive. Seems to be in far back area of trunk. Goes away once clutch is completely let out and slight gas is given. Don't last long and seems to be only at warm up. I'm thinking might be loose exhaust part or heat shield and once hot it's tight again. __________________ Car mods: never enough!

08-19-2016, 04:41 PM	#14
HyperV117 Drives: 2010 Camaro 1SS Join Date: Nov 2015 Location: CA Posts: 358	That video sounded like a loose heat shield. __________________

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