Started taking the head bolts off. I accidentally started with the wrong one in the back. I was supposed to do the lower one at the firewall, but I did the upper. 10, 9, 8, all went fine, and then 7, that lower one by the firewall, I go to do and I see it is nearly rounded off. I've attempted it with an impact socket as well as a regular socket, all 6 point. It just keeps slipping off. PB Blaster isn't helping, and I've re-tightened the other bolts I unbolted to even the tension.

What can I do? The engine has not been pulled. Will a bolt extractor even fit back there? There's no space to drill, at least with any tools that I have.

 

I don't think a bolt extractor has a thin enough lip to fit in the recess but if it does by all means give it try. I've welded nuts to bolts like that but without a welder that's kinda moot. Have you tried a 6pt metric yet? A metric 6pt impact that is just short of fitting and pound it on, it'll square the existing flats somewhat. If you remove the engine mounts it'll lay the engine flat so it's not up against the firewall. You'll want to remove the bolt by hand, no impact.

 

@Irnoob how did you end up getting the bolt off?

 

I bought a set of Irwin Extractors and another brand of extractors, but don't recall the brand. Put the closest size I could on the end of an extension and hammered it on. Took a few tries of it slipping off, but after using a bigger hammer, it seemed to stay on. To get it off, I had multiple extensions, a swivel socket, a large breaker bar, and I believe I had a cheater pipe on the breaker bar. Wrenched as hard as I could and it finally came lose.

I believe I also applied a lot of PB Blaster on it beforehand.

 

I bet it was a huge relief when it broke loose. Bolts rarely have problems when they are easy to get at!

 

Agreed!