redbird555

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

redbird555

Bumpp

C6topless

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 .

OneMoreVet

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!

redbird555

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

redbird555

I also checked the hanger springs, one is really tight and the other I can move with my fingers is that enough to cause a buzz? It's compressed a little but not much at all so it has movemebt

redbird555

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?

redbird555

Just wanted to give an update if someone in the future finds this thead. The issue ended up being. My rx catch can the pcv inside was rattling around making the buzzing noise.