loud exhaust rattle around 700-800 rpm

[jbrush]

ok, working through issues here. my van had a collision recently, and since has had a pretty major rattle in the exhaust between 700-800 rpm. actually, everything in the whole van rattles -- it's like the resonance frequency of the whole vehicle. but the exhaust is really loud!

anyone had experience changing that? i see underneath that there are plastic rings that the exhaust is kind of suspended by, but i think it's also still held in by bolts. i haven't yet found something loose to just bolt tighter -- ideas where to start?

thanks!
.b

[Burntboot]

The wonderful world of rattles, so much fun.
As far as the exhaust goes, rattles usually occur more from clamps than hangers, if it is loud enough to cause a rattle it should be easy enough to find what is loose. first thing to look at is the butterfly clamp at the down pipe. It is a pinch style clamp, just grab the outer plate, if you can wiggle it, it needs to be secured, I ended up taking it apart and installing a new full thread bolt and got it secured that way. Didn't solve the noise though. There is also a clamp just aft of the Y that I also had rusted off, removed and rattle still present.
As to what my noise was, it was actually a combination of things, a lot was coming form the clutch disc, the springs were loose and rattled like crazy, replacing the clutch solved some of the rattles.
In the end though, my issue is with the timing chain, that repair is still pending but I suspect once that is actioned, all will be quiet.

You just need to go through it methodically and eliminate things as you go, a stethoscope is a handy tool for this sort of thing, can be done with a screw driver on the ear bone but the stethoscope makes life a lot easier and they are cheap these days, worth adding to your tool box.
BB

PS - also make sure that exhaust is clear of the frame, it should not be touching anything along it's length, you will need at least a finger width of clearance on all pieces.

[skibum]

Not knowing the age or condition of your exhaust, this might be a stab in the dark, but maybe one of the inner baffles in your muffler let loose, causing a rattle from being loose and a louder exhaust from being gone.

This answer is also directly in response to the question in the subject line. Rattles can be baffling, like Burntboot alluded to. Like he said, they run all over, so focusing on the exhaust may not get you an answer.

You say the whole van rattles. Is this new (since the accident)? I'm not sure what kind of reaction the van might have to the crash, but if that loosened up some "gunk" in the gas tank/line that may be impacting the process at idle, that could cause a rough idle, that would possibly cause the rattle.

Good luck!

[jbrush]

hi folks,

well, there are rattles (just at that resonance) throughout the van, not sure if it's new or not. but the (a?) main issue with the exhaust is that the place where the pipe enters the muffler has come loose, so it bounces around inside. (it's long enough that it's not actually loose -- just bouncing.)

is this the kind of thing a muffler shop will spotweld for pretty cheap? are there other solutions? the muffler is old (original?!), and quite rusty, but otherwise there's no obvious holes.

thanks for the responses!
.b

[micah202]

....simplefix #232......snip up a 'bud' can and jam'er in there...
.......for some reason 'bud' cans seem t'work th'best

hi folks,

well, there are rattles (just at that resonance) throughout the van, not sure if it's new or not. but the (a?) main issue with the exhaust is that the place where the pipe enters the muffler has come loose, so it bounces around inside. (it's long enough that it's not actually loose -- just bouncing.)

is this the kind of thing a muffler shop will spotweld for pretty cheap? are there other solutions? the muffler is old (original?!), and quite rusty, but otherwise there's no obvious holes.

thanks for the responses!
.b

[jbrush]

....simplefix #232......snip up a 'bud' can and jam'er in there...
.......for some reason 'bud' cans seem t'work th'best

ok, here's the much-delayed update. the beer can-stuffing worked, but only temporarily -- the shaking at idle seems to rattle the cut up cans loose after a few weeks. for now, i can just keep stuffing it back.

the shuddering problem is clearly the deeper issue, and a new (more problematic) symptom has emerged, that might be linked (but might not). i'm going to make a new thread for it.

tnx!
.b