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H3T H3T Tailpipe bolts break between flanges/gasket

FactoryOrdered2010AlphaT

Well-Known Member
Messages
87
Location
Canada
Took the spare off in prep for some work and was poking around with a light...something looked...off. The bolts that pass through the 15036012 Tailpipe Gasket seem to have...let themselves go in the middle?

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There a parts diagram here: https://www.gmpartsonline.net/auto-...ne/exhaust-system-cat/exhaust-components-scat
 
Last edited:

RamRod

Well-Known Member
Messages
3,914
Location
AB, Canada
dang!

A muffler shop should be able to sort you out no problem if you don't have a welder.

If you want to fix it yourself you could knock out the sheared off bolts and then drill a hole through the other flange. Then all that would be left is to find a gasket and bolt it back up
 

FactoryOrdered2010AlphaT

Well-Known Member
Messages
87
Location
Canada
find a gasket and bolt it back up

They don't let me play with flames, yet.

One supplier says it's a replacement for 15036012 : https://www.napacanada.com/en/p/FPG61287

Wonder if it burnt through the old gasket before the bolts. There wasn't any indication something was wrong while it was running. We did find the truck bed right over top of that very hot last summer after a 4-hour run - but I didn't see anything out of the ordinary when I looked underneath then. Spare wasn't off though...and I wasn't all the way under the truck.

Had a tune up done 30 days ago by a GM service centre - I reported it felt like it was running rough/cold/excessive vibration when idling even after it had been running for 30 mins - vibration didn't change when shifted to neutral - revs were not bouncing around during that vibration. Of course none of what I reported was actually written on the work order....they just selected the old flush/tune/spark plugs/cha ching and said it was fine.
 

Traxx

Well-Known Member
Messages
682
Location
PNW
Is that the rearmost section? Mine did something similar so I wound up ordering a new tailpipe. You would think it would just slide in from the front or back but nooooo had to remove the bumper and rear trim to get it in.
 

FactoryOrdered2010AlphaT

Well-Known Member
Messages
87
Location
Canada
rearmost section?

Yes, the Tail Pipe section is #10 (94700609) in the diagram below. Interactive version here.

#7 is the Muffler & Pipe (94738538) section starting at the engine side, ending at #11, the half burned out Tailpipe Gasket (15036012) you can see in my first photo. That was shot from above looking outboard ~, so the top side burned out first.

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With that break the tailpipe section will pivot up/down in line with the end of the muffler pipe. It doesn't seem to want to fall backwards more than the gap you see in those photos. Tried pushing it back further to get better photos of the bolt breaks. Maybe that #12 hanger is supposed to let it bounce around?

Why did you elect to turf the old tailpipe section? I'll look more closely at that entire section tomorrow but other than the bolts broken between the flanges and the destruction of the gasket...if the face of the flanges can be cleaned up I'll try to have it repaired.

Repair vs Replace: Trying to figure out if a properly motivated mechanic will even be able to get the right tools in there to remove the broken bolts and mate the two back together with a new gasket without having to remove it. Have a FEL-PRO 61287 gasket in hand already. I'll band-aid it up to a point... Some kids toss the stock exhaust the day they bring the truck home...this one's given nine years and didn't even complain when it was hurting. I inspected the muffler section and it seems ok... I've never had to replace an entire exhaust system but it's always seemed like one of the primary parts that would wear out. Muffler shops must exist for some reason... Is there a replacement exhaust system for the H3T I should be excited to consider sooner rather than later?


In thinking about what caused that break... It's entirely possible (read: probable) that exhaust tip's been backed into snow and mud banks in it's lifetime; the 'mud' flap/wheel well lining a few inches from it is somewhat more flexible than the other side. Maybe contact with the tip translates into the tailpipe section being bent upwards at the join, creating a gap on the top side and promoting that sort of burn through?

I lashed it back together with a dozen or so loops of thin garden wire for the moment. Was -5 C here last night (23 F)...can see nearly all exhaust making it into the tailpipe section...there's still an air gap and the original gasket is more than 50% gone so not surprised to see it leaking from that area still. Wouldn't put a dog back there with it like that. Even if the flanges were cleaned up...this replacement part is so thin I can't see how the two sections would be ever be fully sealed...unless they just torque the hell out of it. But that would lead to...oh broken bolts. Maybe that's how exhausts systems work?

The "excessive vibration" I reported to a GM service center a month ago, which didn't go away after a $750 CAD tune up (~550 USD, new plugs/flush/etc.) That vibration I would feel at stop lights even when it was warmed up and shifted into neutral...is all but gone and the revs seem to have dropped back to 500, where I feel it used to be all the time. Would a tailpipe flange blocking a muffler pipe increase RPM and engine vibration?


Same parts on H3/H3T...so if you've never done an inspection there...you might want to have a look see at the 15036012 Tailpipe Gasket all the way round and preemptively replace it.
 

lowtrac

Well-Known Member
Messages
222
Location
Georgia
You could cut those flanges off, get an appropriate exhaust pipe coupler (I used a 2.5” I.D. to 2.5” I.D. for my post-cat fix) and some exhaust clamps. Not the most elegant solution but it would work and still be removable.


Sent from my iPhone using Tapatalk
 

Traxx

Well-Known Member
Messages
682
Location
PNW
Too soggy out here to go crawl around under the truck looking but iirc there is very little room to work on the tail pipe with the shield in the way so cutting it and welding the sections back together might be an issue.
 

FactoryOrdered2010AlphaT

Well-Known Member
Messages
87
Location
Canada
"...when a plan comes together."

Thanks for the tips. They were able to bang off and out the old hardware, clean up the face and bolt it back together better than a band-aid. Having the FEL-PRO 61287 gasket in hand made it a relatively quick and inexpensive trip to the mechanic. Still a bit of life left in that system...but it's one the long term project list of 'parts that will wear out'. Have to pull the spare down a few times over the next season anyways so I'll have some chances to see how that fix does over time.

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Now where was I on my list of H3T-hings to do... Oh yea, shocks (still stock) or windshield (#3) next?
 
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