2014 Silverado /Borla Catback...WHAT IS THIS NOISE!!???

lemmuhj · December 28, 2015

Here is my 2014 LT. I installed this Borla cat back a little less than a year ago. On cold start ups, i sometimes hear the sound heard about half way in the video. It only happens when i first start the truck. Sometimes i dont hear it which im guessing depends on the outside temps/humidity. I finally have a good enough phone to be able to film and post it. Anyone ever see/hear about this? The catback performs perfectly other than this one little sound upon startups.

I cralled under the truck and made sure everything is tight...even used a rubber mallet and beat around. I had a mechanic friend say that the honeycomb insides of the muffler may have come loose at a weld spot.

http://s1190.photobucket.com/user/lemmuhj/media/Mobile%20Uploads/20151226_093233_zpswcbdmwdv.mp4.html?filters[user]=121025650&filters[recent]=1&sort=1&o=0

joshc64311 · December 28, 2015

idk flywheel or heat shield on the cats?

Badass69 · December 28, 2015

Doesn't that catback have the flapper thing in it like the stock exhaust setup? Maybe that is rattling?

lemmuhj · December 28, 2015

No, no flap thing. Good guess tho, thnks to whomever replies..this is driving me nuts man!

Doesn't that catback have the flapper thing in it like the stock exhaust setup? Maybe that is rattling?

Green 1364 · December 28, 2015

Maybe send the clip to Borla or disconnect the muffler to see if it still does it.

bdbake01 · December 28, 2015

There's just something loose somewhere in the exhaust. Maybe in the muff or a clamp somewhere? I'm with the honeycomb theory. Heats up juuuust a bit, then it's tight.

Eddie 70 · December 28, 2015

Sounds like a heat shield making contact to me. I can understand wanting to quiet that noise.

schmolf4 · December 28, 2015

maybe you need a new muffler bearing, sorry couldnt resist

oldbiker · December 28, 2015

Did your start with your key fob? I think when you use your key fob your air conditioning compressor starts, depending on the temp. Try key start with air off. just a thought.

muddkatt · December 28, 2015

I am pretty sure its not the honeycomb. Had that come loose on 2 different vehicles and it sounds like a rod knocking and never goes away as the engine warms up.

From the video, it sounds like something rubs for a second or two against something spinning like a flywheel or maybe a pulley on the engine.

scott19677 · December 29, 2015

That sounds almost like the starter gear vs. flywheel.

Silver ice 6.2 · December 30, 2015

Well we can all guess... but I would crawl underneath and start the truck.. only down fall after 2 times you got to start the truck with the key. So maybe having another person help with that... try this tip you will find your problem

lemmuhj · December 30, 2015

Thanks for all the feedback guys, will be getting under there soon. Problem is, it does it only once upon intitial startup.

As someone said above, it does ONLY happens when i start with my key fob.

This sucks, because there is no way i can bring this in to dealership for warranty work. It would be a perfect opportunity for them to blame the catback.

Any other advice to find issue? Would disconnecting cat back and starting help locate? I really think its the Borla though.. Shit sucks..

oldbiker · December 30, 2015

Do you have GM/Borla or just the stock Borla without the flapper valve? I still think something is fishy when the noise only happens when you start with key fob.

Willshire · December 30, 2015

Sounds like a rotating part to me. But like it was suggested u need to be under the truck to pin point. Once you are close to it use a long screwdriver to ur ear to confirm