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I pulled header on a car today to investigate loud ticking from exhaust expecting to find a crack and found this. It was a noticeable tick sound-wise but nothing else of note. White pipe is cylinder 2.

Initially I thought head gasket but no signs of coolant ingestion. Plugs all look and smell identical, exhaust port of cylinder 2 itself has black soot in it comparable to the others. Tested cyl 2. injector, it is working properly.

The flanges are no longer perfectly flat (CSC headers) so I assume that the leak was getting bad and could have caused this but....

The white is only present in the primary pipe and secondary pipe within about 5" of the flange in that single cylinder.

Wondering if anyone else has wisdom to share on this. I've seen white from exhaust leak before but usually a bit more localized.
 

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Rob, I've also seen discoloration from exhaust leaks like that, but that is remarkable in how white it is. And you say the #2 port itself looks normal, sooty like the others? Maybe the exhaust leak blowing out at the flange there is being diluted somehow.

I'd say check your compression in all three adjacent cylinders. You got a way to verify the mixture? No loss of coolant recently? I'd clean it up, apply red hi-temp silicone to the gasket, and see what it sounds like afterward.
 

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Rob, if the exhaust leak was at that spot, the introduction of Oxygen could create a "lean" condition at that point. Causing the soot that you see on the other ports to be burned off. Its close enough to the chamber that the temperature is high enough to cause this.
My 2c.
 

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Just a follow up on this thread. Indeed the flanges were badly warped and the leak was causing lean in that area.

Local machine shop ground the flanges flat for about $60. Per JoeCab suggestion, used a small amount of AcoustiSeal (Walker part ) 35959 on the flange faces.

Also sourced brand new 12-point bolts from Detroit Diesel (part number 23521607) to ease re-installation. An 8mm 12-point socket is much easier to maneuver in that tight space compared to a 13mm six-point socket.
 

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Good information there, Rob! The right fastener can make all the difference. I'm still looking for 9mm socket head capscrews for my Spider's u-joint flanges. And looking... and looking. Thanks.
 
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