Mitsu grade 11 is 1 + 1? Options

[ncgalant]

My exhaust manifold bolts that run through to the turbo are genuine mitsubishi bolts that say 11 on the top. As some of you saw I had a couple of them comming lose at the meet a couple of weeks ago, so today I finally got around to pulling them out and throwing in some lock washers.

I started with the two on the engine side, they were already lose and came out easy. When I started into the third one it was a bit more snug but came lose fairly easily. About half way out it got really hard. I thought to myself, give it a sec and started into the next. Half way out it did the same thing. I went back to the other and got another couple of turns on it and before long couldn't even hardly move it. I could turn it back in, but not out any farther. Grabed my GF's car as I was doing this at her house and ran to advance for some PB blaster. Gave both of them a generous squirt and they both came out.

What I saw shocked me. There's now 1/4" of threads missing off of the bolts. It was completely eaten off. What's worse yet is that I had to put those bolts back in. I guess I'll have to replace them but WTF. Losing the threads on a grade 11 bolt, that's just crazy.