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I recently bought some cheap ebay headers for my 2000 civic EX, and When I installed them I immediately noticed almost no low end power and It was very loud coming from the front of the car. I figured this was to be expected with larger exhaust. Until about 5 days later when I get a CEL for running lean and low exhaust pressure. This is when I took a second look and discovered the gasket between the Y pipe and the 4 tubes was completely blown out. I’ve read that over tightening can warp this flange seal very easily, and I might be guilty of that.
I then pulled everything out, took out the fried aluminum gasket (it was literally burned through the side of the gasket) and slapped TWO aluminum gaskets in there. It ran excellent for about two weeks…until I started to hear the raspiness from the front again!! I assume the gaskets aren’t to the point the previous ones were, but when I wipe around the seal of the flange I get come carbon on my fingers. I have yet to get any CEL this time, but I would like not to push it to that point.
My question is for those who have encountered this problem and what you have done to solve it? I’ve looked into JB weld, but it cracks very easy, and being right on the flange, I can see the pipes flexing enough to crack it.
Should I try again with some new cheap headers? Or should I get some 4-1 headers that are one piece? Thus getting rid of the possibility of a leaking seam. If I do get 4-1 headers, will it be less low end power than a leaking 4-2-1 would give?
The simple fix is to put your oem manifold back on. Nothing is going to work better or last longer.
My stock manifold had a rattle at 3k rpms that drove me insane. I'd rather have a raspy leaking ebay manifold than to listen to that every day. But ideally that would be a good suggestion
Those headers are cheap and prone to leak. The issue is youre not tightening enough, up it to maybe 40lb-ft. And use anti-seize, after years these bolts snap. The aftermarket bolts themselves are prone to stripping. Don't use two gaskets, that makes it worse. You will want a new one, those aftermarket 3 piece gaskets are almost a 1-time use and yes I've had this exact part do the exact thing for me. You can get an aftermarket gasket through autozone actually if ya find it on their website, and that at least gives you a warranty so you can get a new one if you screw up again.
The easy fix is to get another gasket and then get some Loctite 30558 (NS 5109) High Temp Gasket Maker. Put a coating on both sides of the gasket and cinch your header back together. Let sit for 3 hours and then it will be sealed.
That stuff has a PSI rating of 5,000 PSI and can handle up to 600F temps on the flange.
I used that on my cheap ebay 2 piece header and never had a leak.
4-2-1 exhaust flange leak!!!
