Exhaust rattle issue

[draper11]

I am getting what sounds like exhaust system vibration at certain levels of acceleration. Tonight, at 1200 rpm under light constant throttle, I almost got it to do it at intervals a few seconds apart. The RPM would lightly tick up as it occurred.

I did have a look under the truck this past weekend. I think the noise is the heat shield before the muffler. I put hose clamps around it which I think lessened the sound. I did not see any vibratory issues with 02 sensors.

Can I be getting some kind of misfire through the system? Do I have a cat issue or some other compromise? Do the rubber exhaust hangers get loose over time allowing excessive shake?

Thanks for any suggestions to look for next.

 

[j91z28d1]

I'm pretty badly at finding rattles but if you got a rubber mallet. you can climb under and tap the exhaust with it. you might find your rattle.

hit the cats too, it's possible the brick inside comes loose and rattles around.

 

[rdezs]

If you had a misfire or a defective catalytic converter, you'd get a check engine light. But yeah, I like the rubber mallet I keep hanging on the wall. Tap on the catalytic converter as well as the muffler and resonator if you have one. Could be just a baffle inside of the muffler came loose. Those big rubber hangers typically don't stretch out, but get harder with age. Heat shields are probably the number one rattle item..... Speaking of heat shields, check if you're exhaust manifolds have the heat shields on them. I've seen a couple of those come loose and vibrate depending on RPM

 

[CTX-SLPR]

I'm having the same sounds and it turns out that the flexpipe just behind the rear most cat is broken (the outer braiding is swollen). Open the passenger door and start it to see if you get exhaust leak sounds as well.

 

[draper11]

I'm having the same sounds and it turns out that the flexpipe just behind the rear most cat is broken (the outer braiding is swollen). Open the passenger door and start it to see if you get exhaust leak sounds as well.

That’s interesting. My braiding was swollen and loose- so I clamped it- how did you find that it was broken? I did remove the pipe to refit the connector. Is there another downstream before the muffler?

 

[draper11]

I'm having the same sounds and it turns out that the flexpipe just behind the rear most cat is broken (the outer braiding is swollen). Open the passenger door and start it to see if you get exhaust leak sounds as well.

How did you figure out it was broken? My braiding seems to be the source of the noise.

 

[CTX-SLPR]

I definitely have an exhaust leak in that location. Poking at it today while soaking the headpipe bolts and it might be the ball joint in front of the flexpipe as that is also a bit loose cold vs. my rattle comes on when it's at temperature mostly.

 

[j91z28d1]

there's been posts from others about that weird clamp leaking. I replaced mine and it still leaks some haha.

if your flex pipe is bad, an exhaust shop could replace it and that style clamp with something else. or just weld it solid

 

[draper11]

I looked at it again last night with a blower and soapy water. The coupling at the flex pipe is letting a bunch of flow through. Both manifold flanges were also blowing bubbles pretty good. I’m assuming I would get improvement by addressing these. I’m hoping I can drop the cats and easily replace donuts?

 

[CTX-SLPR]

I'm dropping my headpipe(s) tomorrow to get to the trans TECHM, already started soaking the flange bolts with PB Blaster in hopes to get them off without stripping/breaking the studs. I'll try to keep a log of how it goes and what the flexpipe looks like once that's down.