So I'm in the process of removing my turbos so I can replace the LIM gasket. I've got a lot of crap torn off the car, and I started removing the downpipe. I sprayed all the threads with penetrating oil, and let it sit for a few hours. The threads on the end of the studs, and the nuts looked perfect, so I didn't think I would have any problems. Well, I put a wrench on one of the upper ones, and it starts to loosen, no problem. Then it gets REALLY hard to turn. So I tighten it back up, loosen it, etc... trying to work it out. This doesn't help at all. So I decide just to use as much force as possible, and if I break a stud, I'll worry about it later. Well, I got the first nut off this way, and it totally ate up the threads on the entire stud! I've never had this sort of problem before. It looked like it had been badly crossthreaded, but I know it wasn't. The second upper stud did the exact same thing, except when I forced it out, the whole stud came out. But the stud threads that go into the turbo are all screwed up! I have no idea how this could have happened... The bottom two came out easily, stud and all.

So then I figure at least I got 'em out and I'll worry about it later, and I'll start on the downpipe-to-cat nuts. I get them started, no problem, and then all of a sudden they get really hard to turn! The exact same thing happened! The threads and nuts looked perfect to start with. I ended up breaking both cat studs, but I finally got the dp off.

Whats the deal here? Do these nuts weld themselves to the studs or something over the years? Usually, at least with my experience, exhaust bolts are so rusted you can't really do anything with them, and end up cutting them off. But these ones looked absolutely perfect to begin with, but turned into a real bitch.

I'll probably have to put a helicoil in my turbo, but I'm not sure what I'm gonna do with the cat yet.

BTW, my car has 86K miles on it. That probably doesn't help.

Paul

 

I think the heat from the rotaries just kill the studs over time. For the dp to cat just drill the studs out and put a bolt in place.

 

As for the cat studs....just cut off whats left and drill the rest out. Then you can assemble with bolts and nuts....no more studs to worry with.