LC engineering header leak/ P0420 code

CLIFFS: I bought an LC engineering header a year ago and found a leak at the flange. Got sent another one and i figured out it has a leak too.

So here we go. This isn’t a rant but I guess I’m just gonna share now that it’s my second header I’ve installed.

initially I threw a k&n drop in in the truck and honestly the truck felt and performed great. Much better than the stock (everyone disagrees but idgas).

i was stoked and ordered a header since I had one on a pickup a long time ago. Got my first header and the truck ran funny. Felt like it lost power. Quite a bit of it actually. Finally tracked it down to an air leak at the base of the header flange.

Shared the video of the leak with LC engineering and they gladly shipped me another one, and I installed it about 6 months ago. Truck drove, but no power increase or anything and still felt kinda sluggish.

I ended up buying a pair of boggers to go have fun with during all this and my truck couldn’t make it up a hill without being tacked out in 4th gear. Truck has 285k on it though so I just figured it was gona take a shit on me or something. So in the effort to maybe make life easier on my truck and regain some power I regeared to 5.29s which really helped the truck out a lot. Engine doesnt strain at all anymore. HOWEVER…

In the last month or two my rig has been reading a P0420 code and I couldn’t for the life of me think of why. I looked for vacuum leaks under the hood n stuff but never found anything. Took truck to the muffler shop that installed a magnaflo muffler for to have them try to dissect any issues with the cats/o2 sensors and they said the cats seemed to be flowing fine. So I was about to buy some new o2 sensors today but decided to go out and squirt some soapy water on my exhaust and hook up the vacuum to the tailpipe and sure enough I found a leak on my second brand new LC engineering header.

I’m not mad or anything although it will be my third header from them and at this point I’d kinda want the header tested first because the labor of getting it in isn’t a quick thing. I mean I’ve done it twice now and know what I’m doing but it definitely bugs me to think I gotta do it again while I’m working and in school.

Should I look at a different header??? LC doesn’t really have a whole lot goin on for the 2tr engines that I remember. I was looking into an engine rebuild kit but they didn’t have one. I know LC is known for being the best and I don’t doubt it, their customer service has been great. But idk. I’m gona chat with them when they get back from lunch and see what they’d want to do. I googled my issue and it seems like I’m not the only one that’s received a header that leaks.

 

Did you install a new donut gasket at that flange, or reuse the original one?

 

Ya I put a new one on. LC sends new ones with the headers when you buy them. I got an email back from them. I’m gona send it back to them so they can check it out.

 

That's odd. How does the rest of your truck's exhaust look, from the flange back? An extra wiggle room for a better fit?

Either their jig changed, or there could also be something with your exhaust.

 

Oh like as far as the fit where the header flange bolts to the rest of the exhaust? At one time I tightened the two bolts too much and could have slightly bent the exhaust flange. But nothings wrong on LC’s end as far as the header flange goes. Only issue is that there was a hole in yet a 2nd header of theirs. But they’re sending another one. I loosened all the header bolts up today and am waiting for theirs to come in so I can do the direct swap and I’ll ship the old one out to them so they can inspect the hole. That’s what she said

 

Old style vs new style. Hoping to god the new one doesn’t leak.

 

Looks like the new header design is not equal length, but hopefully it'll work out for you.

 

ya not sure why they went away from it but at this point I didn’t even care about performance as much as I just didn’t want a header with a leak in it. And so far I’ve had better luck with this header.

 

Both my lce header sets I recently received are the top header in your picture. Hope I don’t have to add that to my problem.
Im sorta in the same boat as you where.

Ive already installed 2 sets of lce headers in the last 2 months and both sets had the ceramic coating flaking off them everywhere within first couple weeks.
I ended up just taking the discount they offered me,
because I couldn’t see how me installing the 3rd set of headers, that they did offer to send me, wouldn’t end with the same result, when lce wasn’t sure of what the coating problem was.

And I also bent my cat pipe flange as you did by over tightening it because the header didn’t line up with my pipe either, so I currently still have that exhaust leak.

Trucks been feeling super boggy lately in the lower gears and I gotta give it extra gas to pass that hesitation, rut.

I was assuming it’s my flange leak getting worse and causing the power loss, but now you got me hoping I don’t have another leak on the header where both your sets of headers leaked.

Also just had a thought that never occurred to me before,
are the inside of the headers also ceramic coated?
and if so, is the coating also flaking off on the inside of the header and possibly clogging up the catalytic converter, maybe that’s what causing my truck problems.
Fingers crossed all is good after I get the flange leak fixed.

 

all good points. My truck isn’t fast by any means— but at least my headers welds don’t leak. I think LCE’s quality in certain places has gone down for them to be running into so many header returns. At least they’re making things right with customers though. It’s also kinda pathetic how little they have to offer for the 2tr motors.

And ya the insides are coated too and ya they could be flaking in our cats I never thought about that.