PDA

View Full Version : Chevy muffler noise



Trouble Maker
04-26-2007, 09:26 AM
2001 3/4 Suburban with an 8.1. What's the clanking noise coming from the inside of the muffler?? I thought it was just a heat sheild that was making the racket, but sounds like it's inside the muffler. Is this a common problem with the Chevy mufflers...Do I need to replace it?

dumbandyoung
04-26-2007, 09:34 AM
2001 3/4 Suburban with an 8.1. What's the clanking noise coming from the inside of the muffler?? I thought it was just a heat sheild that was making the racket, but sounds like it's inside the muffler. Is this a common problem with the Chevy mufflers...Do I need to replace it?
I had a FlowMaster muffler on my 2001 1500 Silverado, and experienced the same noise. I never ended up finding out what it was because I sold the truck shortly after I noticed the rattle.

Beer-30
04-26-2007, 09:59 AM
I have had that happen twice. Once it was the internal muffler "walls" that make up the different chambers. The other time, it was the fact that the catalytic converter had come apart and the debris was lodged in the muffler. Rattling and clanging.
Given the age, I would say either. Although, my 1998 80,000 mile converters are still doing fine, as I just had it smogged with no hint of problem. I just replaced the mufflers last year. I would probably guess it is just the muffler(s).
Change it soon, as the rattles tend to show up in the ECM as pinging or "knock". The metallic sound transfers from the exh into the block, and the knock sensor "hears" it and retards the time. You barely notice it, but it pulls the timing back. Mileage and power will suffer a little.
I had a turbocharged car back in the day that I tuned on real hard. As the power level was coming up, the motor started really twisting against the limit of the motor mounts. The resultant "creaking" of the exhaust joints would cause artificial "ping" for the knock sensor. I had a program for laptops that allowed watching the ECM parameters. Sure enough, under hard acceleration, the knock sensor count would start up. I put a strap on the motor to limit the movement and that took it away. Weird, huh? Point is, exhaust noises will affect ECM.

shippingguy
04-26-2007, 10:09 AM
It is either the baffles inside the muffler or the catalytic converter and the noise is traveling through the exhaust system. Most likely the baffles in the muffler.

Scapegoat1
04-26-2007, 10:11 AM
Its your muffler bearings:D jk
I put a high flow cat and a flowmaster and problem solved

BoneDaddy
05-01-2007, 02:07 PM
Its your muffler bearings:D jk
I put a high flow cat and a flowmaster and problem solved
Are those the pretty CHROME muffler bearings or the standard kind?:)

Trouble Maker
05-03-2007, 09:20 AM
Thanks... Muffler bearings it is...I'll get those changed out immediately!!!!! :)

creepingcharlie
05-03-2007, 11:34 AM
I have heard that those 8.1 burn oil and en return they clog the cat. You may want look into if you have to get it smogged. That also lowers the performance and mileage.

spectratoad
05-25-2007, 10:57 AM
Just an FYI. I had the pinging sound in my exhaust and after reading this thread I had a cat-back installed while I was in Vegas last weekend. Problem solved. :D
Sounded like a baffle in the flowmaster came loose.

shippingguy
05-25-2007, 11:14 AM
Just an FYI. I had the pinging sound in my exhaust and after reading this thread I had a cat-back installed while I was in Vegas last weekend. Problem solved. :D
Sounded like a baffle in the flowmaster came loose.
Very common problem on the Flowmaster. I had it happen twice to me on my Suburban I had.

Beer-30
05-25-2007, 11:18 AM
I would imagine it is a not-so-friendly environment inside there. Plus, FMs are steel so rust becomes an issue after even a few years. Especially if the veh is short-tripped often. The water from the exh settles in the bottom and just sits there while we are at work. Then, a short trip home, and it sits all night. If the water never gets dried out of there, the baffles would be the first to go.

shippingguy
05-25-2007, 11:20 AM
I would imagine it is a not-so-friendly environment inside there. Plus, FMs are steel so rust becomes an issue after even a few years. Especially if the veh is short-tripped often. The water from the exh settles in the bottom and just sits there while we are at work. Then, a short trip home, and it sits all night. If the water never gets dried out of there, the baffles would be the first to go.
Yerah I was also told that excess heat over time can cause the problem as well.

Beer-30
05-25-2007, 11:26 AM
Yerah I was also told that excess heat over time can cause the problem as well.
Like, oh I dunno, pulling a boat? :D
I actually had Allied MeanStreak mufflers on mine (dual 3") and they started rattling something awful. It was starting to piss off the knock sensor from all the metallic pinging. I was thinking the cats (dual factory hi-flow) had broken loose inside and I pictured all of the debris hanging around in the mufflers. It was just all of the internal piping and baffling inside the mufflers that had come loose and rusted.
Two new series-40 Flowmasters solved the problem.

shippingguy
05-25-2007, 12:03 PM
Like, oh I dunno, pulling a boat? :D
EXACTLY!!

Beer-30
05-25-2007, 10:23 PM
EXACTLY!!
When I first put the headers on the truck (7400 Vortec) and the dual 3" pipes along the passenger side, I found out how much heat there really is. I was pulling a friends 21' Malibu tourney boat (4000lbs?) over Tehachepi. My friend in the back seat said, "um, there is smoke coming from between the bed and the cab. I stop and get out. The heat was cooking the thick factory coating on the frame rail and crossmembers.
I don't doubt that the baffles in a Flowmaster glow red during a boat pull over a hill.

2forcefull
05-26-2007, 05:16 AM
When I first put the headers on the truck (7400 Vortec) and the dual 3" pipes along the passenger side, I found out how much heat there really is. I was pulling a friends 21' Malibu tourney boat (4000lbs?) over Tehachepi. My friend in the back seat said, "um, there is smoke coming from between the bed and the cab. I stop and get out. The heat was cooking the thick factory coating on the frame rail and crossmembers.
I don't doubt that the baffles in a Flowmaster glow red during a boat pull over a hill.
the problem is not flowmasters, it's the hispanic copys!!!
everytime someone comes in to my shop with a rattling flowmaster is a copy and not a flowmaster. In almost 30 years of installing them I've yet to have one bust loose inside. and only had a few crack anywhere
Steve
BEST MUFFLER SHOP
LAS VEGAS

Beer-30
05-26-2007, 11:17 AM
the problem is not flowmasters, it's the hispanic copys!!!
everytime someone comes in to my shop with a rattling flowmaster is a copy and not a flowmaster. In almost 30 years of installing them I've yet to have one bust loose inside. and only had a few crack anywhere
Steve
BEST MUFFLER SHOP
LAS VEGAS
Cool. I had some 40s on my Grand National regal years ago, but didn't have the car long enough to wear them out.
I know they are well built, or they wouldn't be the most popular muffler on the planet.
My new ones say Flowmaster right on the side.