Rusty 2003 Denali Cat and Manifold help

[Zach477]

I have an exhaust leak at the manifold and its throwing codes for blocked CATs. Anyone have any tips on getting the exhaust apart? The bolts for the flange connection and headers are pretty much solid rust, to the point you cant even see threads any longer. Sat on one flange bolt for a few minutes with my 1/2" impact and it didn't budge....impact isn't a cheap POS but its also not a high end wrench. Even a breaking bar couldn't get any of them to loosen. Been soaking them in PB Blaster but no improvement. Any ideas?? Thanks

 

[Countryboy07]

Time for long tubes and cat-less Y-pipe... If you don't want to do that, it's time to break out the torch and blow the bolts out.

 

[01ssreda4]

Remove the manifold then separate.