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Discussion Starter #1
Hey all, I'm pretty new to the coiler stuff having spent most of my rover time with the leafers. I'm trying to fix and exhaust leak at the right side manifold to down pipe connection on at 1994 NAS d90. It appears there have been a couple of attempts to fix this I put in brand new gaskets and tightened up things as much as I dare but cant get rid of the leak. It seems to be leaking at the outside rear corner of the flange right near the stud.

Is it common for the flanges to crack or warp? It all looked good on a quick visual inspection. Any tips or tricks on the install that might help?

I'm contemplating trying to put a big C-clamp on there tonight and torqueing that down to see if I can then tighten the nut down more in that one corner.

any help would be appreciated.

Thanks
 

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Right sides do tend to crack but in the y but it's possible. looks like you might be taking off that manifold . i'm sure all that hardware is rusted up pretty good and not securing the pipe correctly. I normally take them off clean and prep all surfaces install new hardware and gaskets just my .02
 

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Discussion Starter #3
Thanks or the input. This is definitely right at the manifold to downpipe connection, not down I the Y. All the hardware seems pretty good, I replaced one stud that didn't look so good. Everything tightened down well so I'll give it another go before I start pulling manifolds. Right now my other vehicle is in the shop so this is all I have to drive till I get that back.
 

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Try loosening the muffler and the left side and re adjust head pipe then tighten side to side could be tweaked alittle
 

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Just went through this on mine. Replaced manifold, no leak. Sucks but she's very quiet now!
 

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About to attempt the same fix and have new gaskets - hope this works. I also have a "rattle" in the exhaust that seems to come from the passenger side of Y pipe when the pipe is banged. It is not hitting the frame so has anyone heard of an internal rattle from the catalutic converter? The again it could be just the gaskets at the flange.
 

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I'd pull the manifold and inspect it carefully for cracks. If it's not cracked it can be reclaimed.
I picked up a sander similar to this (mine's actually a 1970's era Craftsman) at a yard sale for cheap.



I remove the studs and run the flange on the sander to make is clean and smooth, and do the same to the manifold to head face.
Never any leaks after that.

When refitting I use lots of Never-Seez and Nord-lock washers.
When refitting to the head I do the same but use Armor Coat 3/8-16 x 1 1/4" bolts. I haven't found metric Armor Coat yet.
 

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I'm confused... you used 3/8-16 bolts in something that is threaded for metric??
No, the bolts for the manifold to head are 3/8-16.
 

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I'd pull the manifold and inspect it carefully for cracks. If it's not cracked it can be reclaimed.
I picked up a sander similar to this (mine's actually a 1970's era Craftsman) at a yard sale for cheap.



I remove the studs and run the flange on the sander to make is clean and smooth, and do the same to the manifold to head face.
Never any leaks after that.

When refitting I use lots of Never-Seez and Nord-lock washers.
When refitting to the head I do the same but use Armor Coat 3/8-16 x 1 1/4" bolts. I haven't found metric Armor Coat yet.
This, or just get a new one. ;-)
 

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This, or just get a new one. ;-)
Yeah. It wouldn't be worth it for just one, but I have a fair few manifolds to refurbish plus I use it for other things.
 

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Discussion Starter #15 (Edited)
I finally pulled the manifold last night. most of the problem appears to be that the manifold has corroded and lost some material around the outside edges. I'm going to try to sand it down tonight and hope that does the trick. I might have to take between 1/16" to 1/8" of material off to get it flat all the way to the edge.

Is that too much to take off? Looks like it will still have plenty of material left to retain the strength that's needed.

There were no obvious cracks to be seen with a simple visual inspection.
 
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