Yeah, now that I think about it, running hot enough to melt that would probably cause something else to melt too, so that's not it.

Probably what the others said, and like I thought at first, physical interference of some kind.

Dan

 

This happens on the drivers side header...why would it differ from the passanger side? All the tubing is the same size.

 

Isnt the dr. side O2 in the headers and pass. side in the y-pipe? I dunno, I am just asking. The O2 in the y-pipe (pass. side) has no obstruction since its going into a large pipe (whatever size that y-pipe is). On the driver's side it must thread in where the primary tubes merge and the sensor is hitting one of them (like the other said). I dunno, just throwing ideas out to why the pass. side is fine.

 

On MAC headers o2s go in where the primary tubes merge on each side. This is really confusing on how it happened.