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Double ended exhaust manifold stud keeps turning. Need help.

1820 Views 3 Replies 2 Participants Last post by  jobzombi
My O2 sensor has been giving me a code. Some troubleshooting and a loud roar from the engine bay made me check the gasket out; especially after replacing the sensor. Taking the manifold off, I found lots of char-like soot outside of the gasket opening, so exhaust has definitely been escaping from there. When I first went to take it off, the nuts came off too easily, some I just twisted off by hand. One stud came out when removing the nut. Seems to have been screwed in and then soldered in, doesn't look like a weld. Taking off the solder I was able to screw the the stud back in quite well, so it has bite. When I put everything back together, I was able to get only 2 of the studs to around 35lbs/ft. The rest keep turning and or tightening. It is weird. As an example I marked one stud with a marker, the end that sticks out past the nut, and when tightening, it does not always turn the nut with the stud, as in, more of the stud sticks out past the nut, but then sometimes, it will turn with the stud. What's confusing the heck out of me, is that if the nut rotates clockwise, but not the stud, then it should be tightening it, if both the nut and stud turn, since, the stud is screwed into the engine block, then it should ALSO be tightening. In either scenario, the only thing that could be causing the behavior is stripped thread in the engine block, but by now, the stud should have fallen out, especially since when the nut turns, but the stud is still, it keeps pulling more of the stud past the nut. Either the stud should have fallen out, or the stud should have snapped off, but neither is happening. Am I mistaken on all this? What can I do, since I'm not reaching the appropriate lbs/ft. Also, can I replace the double ended stud and just put in a good ole bolt?
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I don't think it should be doing that I was taking my manifold off my XD but one but came out with the stud, but when I put everything back in the stud and nut went in nice and tight. Maybe you stripped enough but not enough to fall out
Never had that happen...I'll try taking them out and putting in a flanged nut instead. Maybe I can get enough threads to catch to 30lbs/ft. I was kinda thinking that may be the case, especially with the solder in there; threads strip, but solder sits in a rut that keeps it from falling out. I'll try heat it up a little to desolder it and pull it out. It will either work, or I'll have to retap anyways.
Follow up to all this mess. The stud in engine block is 10mm x 1.25. I tested the stud itself, after I pulled it out. It has what I though is solder on it, but when I took my propane torch to it, it turned red hot, but never melted. Now it can't be a heli-coil, since to use a 10mm bolt, on a 10mm helical coil insert, it would have to be tapped to something larger than 10mm, so the helical coil could be inserted. Right? When I took the stud out, the whole "solder/coil" was still wrapped in valleys of the threads. In essence, if I just pulled out the helical coil, the remain hole, should be larger than the 10mm that the original bolt was. That is not the case. I took out 6 of the studs and used 30mm flanged bolts instead and I was able to tighten them to 30lbs/ft without a hitch. This makes me think that it was not a helical coil. Issue is that of the 6 studs taken out, one still spins but very little. I think 1/8 turning is better than 6/8. Not sure what the heck was in those holes. I have a tap kit, so I'm thinking of tapping that hole with 11, or 12mm, and just using a new bolt. This way if that still does not work, I still have some room to drill a larger hole for an actual helical coil.
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