Anyone have any tricks for getting off some seriously frozen and stripped self-locking nuts that wouldn't damage the threads on the bolt? The nuts are the ones connecting the downpipe to the exhaust manifold.

So far I've dosed them in liquid wrench, gave some gentle taps with a mallet and wrench, used a breaker bar and even an impact wrench with a stripped nut attachment. Thing hasn't moved an inch and in fact broke a couple 14mm sockets.

My preference would be to not have to take off the exhaust manifold and drop it out of the bottom, just because I'd have replace the nuts and gasket there too. But if it has to be done I'll do it.

https://i.imgur.com/DgE2EB5.jpg

Edit: Linked the image instead because of size.

 

Try some CRC-Freeze off. Ive used it on axle nuts that wouldnt budge and they came out cleanly.

 

Induction heater:

 

^^ badass

 

Oxy acetylene

 

No need for an induction heater coil, just use a torch.

 

Torch it off

 

Will a propane torch work?

 

Yes. Torch it.

 

Propane, Acetylene, that stuff that comes in a yellow can...whatever. If it's a torch, it'll warm up the bolt enough to get it off.

 

Well I hit it with the propane torch for about a little over a minute, gave it a nudge with the socket, nothing. I doused it with liquid wrench to let it settle in whatever new openings the heat created, let it sit for a minute, dabbed it off and torched it for about 2 minutes. Used an impact wrench, absolutely nothing in either direction. Said **** it, and torched it for about 3 1/2 minutes, to the point where the entire downpipe was hot to the touch, tried to use the impact again, nothing.

Is this normal? I double checked they weren't welded by the previous owner, and they honestly don't look that rusty. So at this point I'm not sure what else to do. Would a nut-splitter work as a last ditch effort or should I drop the whole manifold off and just have a shop take them off for me?

edit: Also thank you for the help so far I appreciate it.

 

What torch did u use?

The torch at homedepot with the yellow can is plenty hot. Get the thing red then hit just the stud with pb blaster, wd 40 water whatever. You want the stud to shrink and nut to expand.
Don't breathe in the smoke when you spray it with pen lube.