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Exhaust leak

7057 Views 11 Replies 5 Participants Last post by  LoopOut
Installed DT Long Tubes with motor transplant. Everything went fine as far as the header install goes. BUT. My truck sounds like its 20 year old beater v6 now. It sounds OK for the most part but I can definetly hear some mad exhaust leaks.

First off. When installing the headers I did re-use the manifold gasket as per instructions. It's a 2 layer metal gasket which is supposed to be ok to re-use, so I was told at time of purchase. Just kinda seperated the layers a bit and cleaned between them as best I could. I think my leak may be coming from here, or at least one leak. But how do I find out for sure??? Just feel for hot air puffing out around header flange? Or is there a more accurate way?

Second. when I started the truck today and got under it, even just a idle I could feel a leak around the drivers side header/Hi-flow cat flange connection. When I installed the headers there was only a tiny 1/16 inch thick, round copper ring type gasket that I had to re-use between the hi-flow cats and the new headers. So today I un-bolted the headers at the hi-flow cats and used some High temp exhaust silicone. The Hi-Flow cats have what seems like extra pipe that sticks out past the flange face, I would guess to go into the end of the header and make a better seal, But wonder if that isn't leaving potential for the leaking? After I silicone it, think it may have helped a little, but still hear the leak. And after the amount of silicone I used, im pretty certain its a bad header flange leak. So now if Im gona unbolt the headers to install new gaskets, is there a better type of gasket to purchase?

And also to any others with headers, Do you think it would be beneficial to use the extra stud/bolt holes that are on the motor, to help secure and seal the headers better?

Any Advice???
For a truck that has like 19k miles on the motor, brand new Long Tube headers, brand new hi-flow cats, new custom Y pipe and muffler, and Uprev, it sound like a piece of junk that has a broken exhaust rather than custom. :censor:
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Hey Nick.
Who better to answer my question. LoL. I have/had 2 different locations leaking. At the head and at the collector flange.
I unbolted the collector flange from the hi-flow cats and put a bunch of High Temp silicone in there, along with the little copper ring that was on the end of the hi-flows before I installled the headers. And I don't think they squeezed right tight, but very little gap if any. I think that leak has stopped. If not, I guess I will try and find some sort of gasket fix for that.
As for the leak at the head. So, I just buy this copper coat spray, unbolt headers, remove gaskets, spray gaskets and flanges then re-install? Is this stuff just a type of spray on gasket? Or if I have to unbolt the headers anyhow, should I just buy new gaskets?

Thanks for jumpin in Nick.
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Andrew: Yeah, im gona go see if I can find some gaskets for both locations, Head and collector. I would agree with you that, that would probably be my easiest solution. And there are I believe 6 bolts per header at the motor, 3 top 3 bottom(could be 4top 4bottom). Regardless, there are a bunch of extra holes in the motor, and on the header flange. I don't really understand why? But there are enough extra holes that it made me question if I was supposed to use more.

My friends mom is a nurse so maybe I will see if I could borrow a stethescope(spell??). How do I check with them.... I assume I would just pass it over the edges of the header flange and just listen for when it gets louder?

Thanks for the input.
959: Yeah, aside from the leak, I can't say I really notice any rattle can noise anymore either (kinda weird they did that). It does sound like it's fluttering though, (kind of like a burble but not, sounds kinda like a Subaru WRX with exhaust) and does it nearly all the way through the RPM range. I need to re-work my setup to make it sound a little more to my liking, so maybe that will fix the fluttering sound too. I broke down and bought some FelPro manifold gaskets today for $15/pair, for that price I couldn't be bothered trying to use some spray to fix it. So should be no problem after they go on (fingers crossed). Sound clip may be an issue, A) I don't know if I have a device to do so that wouldn't suck, B) I don't know how to upload vids or sound clips, unless it's the same as pics through PhotoBucket.

Tanner817: Sh!t. Maybe I should have tried tightening those bastards first. Oh well, can't go wrong with new gaskets. As for the collector leak, Im gona try and see if I can find some of those "donut" type ring gaskets. They're a really soft metal and have a tapered edge to them. If I find 'em I'll post a pic so you can maybe have a better solution too.

Thanks for the input guys.
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OMG. Just finished taking headers off and putting on new gaskets. Fu(k me. I started at about 1am, didn't finish til 10am. Had more problems second time round then I did the first. 2 studs decided to strip right out on me. Luckily knowing my luck with repairs, I had grabbed a couple of new ones for when I originally put the headers on, just incase. Hope it fixed the problem. Too tired now to even want to start it and find out if it did fix the leaks. And figured let the high temp silicone on collector joint dry a little. Will update with good news later hopefully.
So, finally got the nards to start up my truck today. I was too affraid to start it yesterday morning after 8hrs re-installing the headers with new gaskets, just to find out I still had a leak.
WOOHOO, no more 20year old beater sounding exhaust for me. No leaks to be heard. Now I just gota get a good resonator and/or new muffler to make it sound less like a car. The sound isn't horrible, but it's just too car"ish" to me. These trucks should be able to sound way BEEFIER, than mine does.
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