Headers on a 6.2L with Stock Muffler/Cat-Back?

[ls1frc]

Both slip joints are confirmed leaking. Can see the soot as well as the condensation leaking out on cold start.

With aftermarket cats they have to get hot before they filter enough thus it makes sense that it would go right inside.

I'll try to seal them up and report back. I just drove the truck tonight and the sound is perfect with headers to stock catback, would suck to have to take them off.

 

[ls1frc]

Fixed my leaks.

I had leaks at every single connection. Ball socket, slip fits, and rear ball socket to muffler connection. Used the shop vac in the tailpipe and soapy water technique. Smell is gone after fixing that.

Only issue I have now is after the lifter swap to Morels (they are LOUD) the headers are amplifying the noise badly in the cabin with the windows up. Any suggestions? I really don't want to have to go back to Manifolds. Love the sound with the windows down, but up and no radio/AC on and it's pretty annoying.

 

[avalonandl]

The headers are amplifying the Lifter Noise?

Have you tried putting Dyna Mat on the underside of the engine cover?

 

[91RS]

All LS engines have noisy valve train and the noise is amplified with long tubes. I thought I did something wrong when I did the cam in my SS but its still going strong 25k miles later. I did change to better oil, Redline 5W-30, which made a huge reduction in the noise. I've always used Mobil 1 before and didn't see much reason to use the "boutique" oils but now I use Redline in all of my vehicles.

 

[ls1frc]

All LS engines have noisy valve train and the noise is amplified with long tubes. I thought I did something wrong when I did the cam in my SS but its still going strong 25k miles later. I did change to better oil, Redline 5W-30, which made a huge reduction in the noise. I've always used Mobil 1 before and didn't see much reason to use the "boutique" oils but now I use Redline in all of my vehicles.

Yeah I've been in the LS game since 2008. Had multiple cammed and header vehicles so I know what to expect.

This sound I am hearing is just a different resonance than normal. I think it's because the Yukon is so heavy, it's always in this high load area when in low RPM which is where I hear the resonance. With the cars, you don't hit this area at low RPM because they're half the weight.

It's not a drone, it's hard to explain. Kind of like an air rushing out noise, which makes sense since the collectors are right there at the floorboard.

It's the same noise this guy complained about in 2013. I may just live with it because the 5.3 is actually fun to drive now with all the mods and I know it'll lose 20-30 hp going to manifolds.

https://www.performancetrucks.net/f...ce-21/arh-possible-kooks-header-noise-519538/

 

[ls1frc]

Wondering if the "tinny" resonance has anything to do with feeding these high flowing headers into the stock, restrictive exhaust and there is some back pressure being built up.

Wonder if swapping that portion out may change the sound at all. Doubt it, but worth a shot maybe since my stock catback is rusted to shit anyway.

 

[iamdub]

Wondering if the "tinny" resonance has anything to do with feeding these high flowing headers into the stock, restrictive exhaust and there is some back pressure being built up.

Wonder if swapping that portion out may change the sound at all. Doubt it, but worth a shot maybe since my stock catback is rusted to shit anyway.

At stock/near stock power levels (no boost, nitrous, etc.), the stock exhaust really isn't so restrictive. More accurately, the tubing is sized properly. It's the muffler that's the biggest choke, inherent to its design. It's quite oversized to reduce the choke while still effectively muffling, so even it isn't so bad.

I've always heard a sort of pinging/sort of ticking/sort of ringing sound from equal-length/long tube headers that was from where the primaries met that open area in the collector, which is also right at the floorboard/lower firewall. Thicker steel, heavy coatings or wrapping reduces the sound. I recently installed some tri-Ys and that sound I was expecting wasn't nearly as prominent. My guess is it's because the tri-Y design separates the pulses so they're already attenuated upstream before they hit the collector. The headers are 14 gauge and supposedly are coated three times on the inside and five times on the outside. With it running, I walked around underneath it to listen for that sound and it seemed to be loudest near the first bend of the Y-pipe, which isn't coated. I may wrap it in the future after I get the rest of the exhaust how I want it.

 

[DRKN57]

Loud is a matter of opinion, lol


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[ls1frc]

At stock/near stock power levels (no boost, nitrous, etc.), the stock exhaust really isn't so restrictive. More accurately, the tubing is sized properly. It's the muffler that's the biggest choke, inherent to its design. It's quite oversized to reduce the choke while still effectively muffling, so even it isn't so bad.

I've always heard a sort of pinging/sort of ticking/sort of ringing sound from equal-length/long tube headers that was from where the primaries met that open area in the collector, which is also right at the floorboard/lower firewall. Thicker steel, heavy coatings or wrapping reduces the sound. I recently installed some tri-Ys and that sound I was expecting wasn't nearly as prominent. My guess is it's because the tri-Y design separates the pulses so they're already attenuated upstream before they hit the collector. The headers are 14 gauge and supposedly are coated three times on the inside and five times on the outside. With it running, I walked around underneath it to listen for that sound and it seemed to be loudest near the first bend of the Y-pipe, which isn't coated. I may wrap it in the future after I get the rest of the exhaust how I want it.

Yeah my truck is slow, definitely not a restriction. I think some sound deadening is my only option. Worth a shot before manifolds go back on.

Loud is a matter of opinion, lol


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Truck isn't loud, the sound is just an annoying frequency.

 

[ls1frc]

I took a video of the noise, it's very clear in the video. Listened to old videos from 2011-2014 of all my header cars I had back then and none had that constant "chirping" noise. They just sounded clean. They all had catbacks too though.

Basically, less noisy version of what this dude is also dealing with.

 

[mikeyss]

What's the problem?

 

[kbuskill]

Yours is definitely less pronounced than the guy's in the second video.

I listened to yours first and couldn't hear any problem and then I listened to the second video and heard his plain as day.

I went back and listened to yours then and could faintly here it.

It's definitely strange. Never heard that before.

Maybe it's a slight leak somewhere causing it, almost like a whistle?

 

[ls1frc]

Yours is definitely less pronounced than the guy's in the second video.

I listened to yours first and couldn't hear any problem and then I listened to the second video and heard his plain as day.

I went back and listened to yours then and could faintly here it.

It's definitely strange. Never heard that before.

Maybe it's a slight leak somewhere causing it, almost like a whistle?

I appreciate you taking the time to listen.

I checked for leaks by hooking a shop vac into my tailpipe and spraying soapy water around the joints. I had leaks at the catback to y-pipe, both slip fit joints on the y pipe, and at the collector ball socket connections.

I was able to seal those up with copper RTV and they don't show leaks with the soapy water anymore.

It could still very well be leaking under actual load though. I was getting a smell in the truck before fixing the leaks but that has gone away now, so if it's leaking it's very minor.

 

[kbuskill]

When you say you hooked up a shop vac to your tailpipe, I assume that you were blowing air in to pressurize the exhaust and not sucking air out to create a vacuum?

Did you spray the soapy water around where the headers meet the heads?

If you did, perhaps spinning the engine over just a little and trying it again just in case the valves (overlap) were open on a cylinder and not allowing pressure to buildup because it was flowing through the head and out the intake. Just thinking out loud.

 

[ls1frc]

When you say you hooked up a shop vac to your tailpipe, I assume that you were blowing air in to pressurize the exhaust and not sucking air out to create a vacuum?

Did you spray the soapy water around where the headers meet the heads?

If you did, perhaps spinning the engine over just a little and trying it again just in case the valves (overlap) were open on a cylinder and not allowing pressure to buildup because it was flowing through the head and out the intake. Just thinking out loud.

Yes, shop vac on "blow".

I clearly saw the bubbles out of all the joints I mentioned. I only checked the headers->heads connection from the engine bay with the soapy water. I am going to get under there tomorrow and spray from the bottom.

Good idea on turning the engine over and trying.

I remember on my G8, my ARH headers had a pinhole in the weld in a primary. It made a similar noise as this. How I found it was one header primary had a much different temperature than the others. I'll grab my infrared thermometer and check each primary.

 

[kbuskill]

Yes, shop vac on "blow".

I clearly saw the bubbles out of all the joints I mentioned. I only checked the headers->heads connection from the engine bay with the soapy water. I am going to get under there tomorrow and spray from the bottom.

Good idea on turning the engine over and trying.

I remember on my G8, my ARH headers had a pinhole in the weld in a primary. It made a similar noise as this. How I found it was one header primary had a much different temperature than the others. I'll grab my infrared thermometer and check each primary.

Spaceballs is great... gotta love Mel Brooks movies... Blazing Saddles is still one of my favorites... lol

Keep us posted on what you find... I am intrigued.

 

[ls1frc]

Aha!

Not sure what to do now since RTV didn't hold up. Gonna try rotating the bolts so the bolt is pulling right on the leak and retightening.

 

[ls1frc]

Going to try one more different sealant as recommended here

https://www.svtperformance.com/threads/the-dreaded-kooks-l-t-colletor-leak.1025346/#post-14343931

 

[79jasper]

Could you use a band clamp? They're about 3 inches wide. Will reform to fit over a joint. Use them on flex pipe to pipe joints all the time. That's how much they clamp down. Seal pretty good.

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[ls1frc]

Don't think a clamp like that will work with this connection.