liquid wrench works.

 

these bolts are stubborn.... this past winter simplemanlance and i had to work on his dads truck, replacing them because 4 bolts broke on the rear of both sides and exhaust leaks where horrible!

Anyways we cut all the heads off the bolts and then welded nuts onto the stubs that where left out. between the clean surface to put a wrench on (no rust now) and all the heat they all came out without a problem! Note before we did that we broke 2 heads off. thats why we went that way. didnt want to risk one breaking off in the head

hopefully it doesnt come down to this way for ya. Good luck!

 

I bought a propane torch today. I used it on the crank bolt and it came right off. Hopefully it will be the same case for the manifold bolts. I will try tomorrow.

 

Well I got them off this morning. Used the torch and muscle on three of them, and just muscle on the other three. Finding a position where I could use my leg to push the wrench really helped too. I didn't break any of them. But I bought some new nuts anyways.

 

Having the same problem right now. I may have to get a torch tomorrow. I was turning so hard, I twisted 1 of my extension heads.