Seized Header Nut - Help?

[xray]

Two thoughts:

1) "Header replaced last year" and rusted/seized nuts and bolts don't seem to go together unless you're in a real humid environment. Seems more plausible the nuts got cross-threaded by the impact wrench and mechanic who may not have been paying attention.... If that turns out to be the case, you may have to have the manifold studs cut to remove the header, then each stud manually extracted, followed by (maybe) retapping the stud hole...

2) If they are truly rust-seized, I would affirm the above-mentioned techniques. After soaking with penetrant (Kroil or PB Blaster) consider tightening the nut slightly (1/4 or so turn), then loosen. Once it begins to loosen, tighten it up a little, then loosen it some more. Use this "two steps forward, one step back" approach to slowly work the nut off. The shearing force of the friction produces some serious heat and can snap off the bolt if you're not careful. Brute force is not your friend, finesse and patience are....

Good luck,

Steve

[Arvin_a]

Hey all, sorry to resurrect a long-dead thread, but I just wanted to thank yall for all the help. I got a can of kroil and a set of craftsman bolt-out sockets for rounded nut heads. They worked perfectly together! I installed the aftermarket header and it sounds great.

here are the casualties: