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Chevy Silverado and GMC Sierra Exhaust System Questions



  • i have a 95 gmc with the 350 tbi motor, i have flowtech headers and then 2.5" pipe running all the way back with a h-pipe from flowmaster right after the headers and no cats with two super 44series and then it cuts out right after the rear axle to keep it hidden with no tips, its got a great low, high horsepower sound with no rasping at all and everyone that hears it seams to like it and yes it still is loud but sounds good
  • Okay now I'm confused I've done dual exhausts on several vehicles and this one has stumped me. I'm Running 2.5 inch Duals from the Manifolds back. I'm Using Holly RedHot glasspacks on each side. With the vehicle in park reved up to even 4k the trusk has a nice purr not overly loud but just enough for the good dual sound. I put this thing on the road yesterday and MASHED the pedal to see what it would do. The minute the engine broke 2500 RPM this thing sounded like it had NO exhaust whatsoever. I pulled the glass packs to see if i had one in backwards cause they weren't marked for easy installation and i've taken them off two or three times while tweaking the pips to make sure they fit perfect. The glass packs were installed properly. I Also noticed i have a MEAN tick in the donut gasket on the passenger side so i pulled the pipe at the manifold and checked the donut ring. it looks fine and seals properly to the naked eye. Both rings got replaced when i put the duals on so i know there is no wear in them and this was the trucks first run. ANYONE got any ideas. I'm stuck as to why this things gets so loud at higher rpms but only under load. Oxygen sensor reading show normal at idle and it never kicks the S.E.S. light on so i dont think its bad burn. The passenger side has a little funky smell to it when first running but i think that might be cause the truck hasn't run in like 7 months and it was running lean a little rich while the computer was resetting. (battery has been out for the whole 7 months so computer had to reset)
  • hi i have a 2007 shortbox reg cab 2wd sierra(new body style) and ive intstalled tru duals with glass packs. sounds like the garbage i thru out last night. i was wondering does anyone know how to bypass the o2sensor and co sensors on either side of the cat. any info would be great thanks!!
  • I just purchased a 1996 chevy tahoe 4WD, and we have changed the oil. it still had lots of exhaust smoke, but less than it did before the oil change. After maybe 20 minutes of driving,there is always white smoke and fumes. please let me know what is going on. :(
  • obyoneobyone Posts: 8,054
    edited April 2010
    White smoke is not good. Usually indicates a blown head gasket. The reason there is less of it after the oil change is because the new oil has less coolant mixed in with it.
  • glock75glock75 Posts: 1
    Kommeat, I have a gmc 3500 with a pass side leak that sounds like the doghnut did u fix urs and if so what was it mines also a tick. Thanx
  • I have a 2004 gmc sierra 3500 with a 6.0 gasoline engine and just got a new long tube headers for it but don’t know how to do the exhaust design and I have a borla muffler so dose any one have any useful ideas I mean should I make it with one in put and two out puts or the opposite or two out and two in and what pipe should I use Y pipe, X pipe or H pipe what is the best to get the most power and an aggressive truck sound.

    :confuse: :confuse: :confuse: :confuse:
  • durmax07durmax07 Posts: 1
    We just traded a 2002 Chevy Silverado 1500 HD with the 6.0L and 4:10 rear gears. Back in March 10 I heard the exhaust leak and thought it was the exhaust gaskets, however it was the manifold bolts. Only 2 bolt on each side were holding the manifold on. I got lucky and the mechanic was able to get them out without pulling the heads. Cost $1200.00
  • obyoneobyone Posts: 8,054
    $1200 to tighten the exhaust manifold bolts?
  • davejrdavejr Posts: 1
    I took my truck into the dealer yesterday to have the exhaust manifold replaced. This is after I had been complaining for months about a leak and the noise it was making. And by the way, at 50,000 miles the dealer replaced the cam and lifters becuase they had worn to the point that the engine was making strange noises. This will be my last American made vehicle. Should have stayed with my Nissans, Toyotas and Hondas......Out 360,000 miles on my last Nissan before the timing change stretched and began to run rough. In 70,000 miles this GMC has spent more time in and out of dealerships than it has on the road.
  • I am sorry that your Sierra has not been a satisfactory vehicle for you. Is it still at the dealership for repair, or have you gotten it back? I look forward to an update on how it runs after the dealer visit, and if we can be of any assistance, please let us know in an email with more information on your situation.

    GM Customer Service
  • I have the same issue on my 2009 Chevrolet 2500HD. This truck has never been abused or used for towing yet. I went to the dealership yesterday and they told me this is not covered under my warranty. I came home and looked at what is covered, and it says "manifolds" in the items listed. I'm going to follow up AGAIN with the dealership and try to get them to pay to fix something that was poorly engineered. Perhaps Sarah can suggest who at GM I can contact to get this resolved???? I payed enough for the truck that some simple exhaust bolts should be fixed.
  • Good evening,
    We'd be happy to look into this further and move towards a resolution. Please email us at with the following information so we can get a case started: your name and Edmunds username, phone and address, the last 8 digits of your VIN and current mileage, and the name of your involved dealership.

    All the best -
    Sarah, GM Customer Service
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