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Exhaust - how long do they last? (Northeast)

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nhhandyman

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Nov 27, 2017
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Been searching through this forum with little luck.

I have a '13 Black Diamond Avalanche which just hit 150,000 miles and the exhaust is sounding a bit loud - I don't see any obvious holes/leaks EXCEPT for the expansion joint which has let loose on both sides (a retaining ring was just dangling around on the pipe on both sides). The joint itself is VERY loose and easily moved around.

Are these things prone to leaking/dying and if so are they replaceable without welding (I have a MIG but I'm not very good...)
 
Realistically speaking, depending on how much drive in salty slush, the factory exhaust can last you a good many years. I mean, you were under there, how was the metal looking? As long as there isnt any more than surface rust (no dents/ dings/ deeper rust) then it will be fine.

As for your expansion joint, I wish I had a picture of what the area looked like. Aftermarket solutions don't tend to have expansion joints as part of their design so it's hard to reference the OEM intent.

In your particular case, the exhaust may have been disconnected in order to repair something. (like dropping the transmission). And may have never been hooked back up properly. Im going to assume that the retaining ring you were talking about was some sort of exhaust clamp that is loose. If so, you might be able to just slip that back over the sleeve and tighten it down snug. Though I'm curious as to why the other end would be loose if there was no matching ring in sight. I mean, are we talking clean pipe cuts on both ends of the joint? Is the joint damaged at all? or is the pipe broken? Does everything involved share a similar petina? (does it all look original?)

I know the flex joints are often a point of disassembly for the exhaust, but i'd imagine that one endis meant to be welded in place while the other can be clamped for future removal if necessary.
 
Side note, any broken off bolts on your exhaust manifold? I'm down 1 bolt on each side so far, both are the rearmost bolt.
 
20210419_112131.jpg
the 'rings' were very thin metal on each end. Perhaps to hold the mesh together.
Those rings most likely fit into the small grove you can see.
 
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I'd clean the mud off of the muffler, but otherwise it's probably fine.

That flex joint does look a little frayed and those rings you were mentioning may indeed have been the original piece that clamped down on the braiding.

It might be normal, but something about that weld seems non-oem. If it was re-welded, they might have thermally stressed the flex joint.

To that extent, there's also little you can do about it aside from cutting out that section and replacing the flex joint or replacing the entire exhaust all at once. I'd imagine trying to weld anywhere near that joint would just cause those steel fibers to melt and you would never be able to reattach them.

Like Bainman said, i'd definitely be checking the manifold as well as where the exhaust comes up to meet it at the flange. Those are the natural failure points of an exhaust outside of rust and physical damage

People used to put a couple washers/ pennies in the flange in order to make the exhaust louder on the cheap. Its amazing how a tiny gap can have an effect.
 
Thanks.... I figured it was going to be a cat-back replacement but from what I have been reading those flex items are optional. Because this is the last year of the model, I know sometimes the factory will scrounge up a few pieces from other lines (happened with my 95 E36).

I did find one on a cardi site (attached image) - website: https://www.carid.com/2013-chevy-avalanche-exhaust-parts/walker-exhaust-systems-115251412.html

Of course getting that first flange fitting off will be a little bit of a nightmare.....any time I do exhaust work I end up buying new tools - I think I've got everything i need then BAM - off to Harbor Freight for a 'one time and done' tool.....53888.jpg
 
Yeah, it is considered optional, it more or less deadens the sound of the exhaust from rattling against the frame and sending motor vibration down the length. But it isn't technically required. The 2500's for example I don't think have one even with the larger engine. Now obviously would be the time to get creative with an aftermarket solution for a different sound profile if you wanted. But id presume that like myself, you would just assume have it stock.

Obviously you'd wait until you had the part in hand before doing anything, but theoretically you likely just need a sawzall and your mig. The preformed ends should fit over and inside your existing exhaust if designed correctly.
 
Thanks - before I head out today I'll start her up and stick my head under there to see what it sounds like at that location..... might put the welding glove on and move it around a bit too.
 
nhhandyman said:
Thanks - before I head out today I'll start her up and stick my head under there to see what it sounds like at that location..... might put the welding glove on and move it around a bit too.
Click to expand...
I remember when googling around yesterday, I had seen mention of people hooking shopvac's blower end up to the tailpipe and using it to pressurize the system, and then using a bottle of soapy water to test for leaks. Though i'm not sure how helpful that would be here.
 
HA! I'll use the leaf blower :)
But actually - not a bad idea for my step-son's Jetta that he feels has a leak (sounds different to him) and I can't squeeze under that !
 
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