Exhaust buzzing?
Thread Starter
Drifting
Joined: Nov 2009
Posts: 1,385
Likes: 102
Exhaust buzzing?
So guys a couple weeks ago I put a set of kooks headers orx and z06 mufflers on my ls3 and all was well. This pst weekend I switched out the axle backs to zr1 mufflers and all was ok for about a day. Over the past couple days I get a very faint but noticeable buzzing sound from under my feet up front. It happens on a cold start and then at times letting out the clutch or driving at a very low speed.
At first I was scared it may be a noise from the clutch or torque tube but the noise is present clutch in or out and stopped or rolling. So that leads me to believe it's the exhaust. I can't replicate it on command and it seems to come and go very quick this morning it did it for a solid 20sec when cold then completely stopped and was quiet the whole way to work. It is much more present when cold and once warm very hard to replicate.
I got under the car yesterday and looked around a little and everything seems to be clear up front so any ideas? Is there anything that commonly hits or can rattle with resonance? I had an o2 that was loose and rattling when I installed the headers but tightened that up a couple weeks back and it was fine since. I don't see the heat shields being loose around the headers either but I could give that another look
At first I was scared it may be a noise from the clutch or torque tube but the noise is present clutch in or out and stopped or rolling. So that leads me to believe it's the exhaust. I can't replicate it on command and it seems to come and go very quick this morning it did it for a solid 20sec when cold then completely stopped and was quiet the whole way to work. It is much more present when cold and once warm very hard to replicate.
I got under the car yesterday and looked around a little and everything seems to be clear up front so any ideas? Is there anything that commonly hits or can rattle with resonance? I had an o2 that was loose and rattling when I installed the headers but tightened that up a couple weeks back and it was fine since. I don't see the heat shields being loose around the headers either but I could give that another look
Pro
Joined: Mar 2011
Posts: 534
Likes: 33
From: Southern cali
if what you say is accurate, it sounds like you have a leak where the headers connect to the muffler at the connection point. I say this as you say the sound goes away when heated ( metal expands when heated -- the leak point is closing when hot... thus pointing to a connection point / gasket issue ) ... you can check the connections with a little soap and water ( when it is not fully heated up ) .. see bubbles, that is where you have a leak .
Burning Brakes
Joined: Jan 2014
Posts: 1,070
Likes: 297
From: The other New York
St. Jude Donor '25-'26
Not certain if your car has transmission cooler lines but mine (MN6 Z51) were resting on the header collector next to the starter. In hindsight I heard a buzzing noise within a rpm range that I now suspect was the cooler line. Kooks supplies a bracket that moves those line enough so they don't rub. Here's the result of the installer not using a $3.00 bracket! 
Thread Starter
Drifting
Joined: Nov 2009
Posts: 1,385
Likes: 102
I'm pretty sure mine are clear but I'll give it a look today thanks guys. I retightened everything. Last night and nothing seemed looseZ the noise seems most prevalent in the morning on a cold start clutch in or out doesn't matter. Then while driving it can be heard usually when you slip the clutch quickly enough to jolt the car a bit
Thread Starter
Drifting
Joined: Nov 2009
Posts: 1,385
Likes: 102
Everything seems tight underneath, I really tried to get a better idea of the noise today. Its most prevelant when releasing the clutch from a stop which caused me to think it may be something in the driveline. However I also hear it at times just accelerating at low rpm or idling with the clutch in or out. I just cant see it being something in the driveline because theres so many scenarios it occurs in.... Anyone have more input?
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