06 Corolla Exhaust Noise Issue

#1
Thanks for having me, I'm currently having an issues with my 06 Corolla S (1ZZ-FE) exhaust system. I continue to hear exhaust noise (as if the exhaust manifold or related components are still loose)

1. I have changed the exhaust manifold gasket (manifold to engine) and torqued the nuts to specs (rechecked them for tightness after).

2. The exhaust manifold flange gasket/ring has been changed as well (it is the correct size, new spring kit installed).

3. There is no play or separation where the exhaust manifold down-pipe and exhaust join at the flange.

4. When i had the exhaust manifold off the engine i didn't see any noticeable cracks in the exhaust manifold itself.

5. Upon initial startup of the vehicle a hint of exhaust enters the HVAC system and its noticable.

This noise is most notable when I'm inside the car and initially accelerate from a stop. Its loud almost as if the car has no muffler system. The noise lessens as you let off the accelerator pedal or once the vehicle goes through the transmission gears, but it continues from the start of acceleration until the engine no longer need to work as much as the transmission goes to higher gear ratios.
I'm convinced that the exhaust manifold has a crack that i may have overlooked. Are there any other gaskets i'm missing at the flange besides the ring that installs where the down-pipe and exhaust system join? I have repeatedly check the exhaust manifold bolts, none are loose or am i using the wrong brand exhaust manifold gasket (i used the metal fel pro gasket). From what i could see with the car on a lift there were no other notable leaks in the exhaust system. I will check again to be sure i didn't miss anything.
 
#2
From this pic seems there’s a gap where the manifold downpipe and exhaust system join.


QUOTE="one_uneek_man, post: 42439, member: 11646"]Thanks for having me, I'm currently having an issues with my 06 Corolla S (1ZZ-FE) exhaust system. I continue to hear exhaust noise (as if the exhaust manifold or related components are still loose)

1. I have changed the exhaust manifold gasket (manifold to engine) and torqued the nuts to specs (rechecked them for tightness after).

2. The exhaust manifold flange gasket/ring has been changed as well (it is the correct size, new spring kit installed).

3. There is no play or separation where the exhaust manifold down-pipe and exhaust join at the flange.

4. When i had the exhaust manifold off the engine i didn't see any noticeable cracks in the exhaust manifold itself.

5. Upon initial startup of the vehicle a hint of exhaust enters the HVAC system and its noticable.

This noise is most notable when I'm inside the car and initially accelerate from a stop. Its loud almost as if the car has no muffler system. The noise lessens as you let off the accelerator pedal or once the vehicle goes through the transmission gears, but it continues from the start of acceleration until the engine no longer need to work as much as the transmission goes to higher gear ratios.
I'm convinced that the exhaust manifold has a crack that i may have overlooked. Are there any other gaskets i'm missing at the flange besides the ring that installs where the down-pipe and exhaust system join? I have repeatedly check the exhaust manifold bolts, none are loose or am i using the wrong brand exhaust manifold gasket (i used the metal fel pro gasket). From what i could see with the car on a lift there were no other notable leaks in the exhaust system. I will check again to be sure i didn't miss anything.[/QUOTE]
 

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#3
Did you replace the donut gasket? It's located at the bottom the header where it meets your 1st catalytic converter?

The exhaust noise is it a rattle sound?
 
#4
i did replace the donut gasket but i still get the sound sometimes, i have notice that springs may be in a compressed position sometimes when i park it (driveway is uphill). Maybe the springs aren't strong enough? Its not a rattle sound, more of a "no exhaust" noise and it sounds like there is a separation right where the flange and muffler section meet.
 
#5
I replaced the spring bolt kit. i took pictures (the second pic was too large) this morning and it seems like the springs give way pretty easy. I have attached a pic where the spring kit install and its current position. The driveway has an incline and i'm thinking that maybe the system separates a bit when i enter the driveway.
 

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