Exhaust leak

[Sugar16]

So I finally got around to looking at my exhaust leaking. I was hoping that it was just a cracked manifold like you normally see but it seems that my manifold is good. What I did find was the my rear mounting bolts on number 6 and 5 cylinders are messed up. I felt # 6 to be loose so i started to loosen it by hand and you can see how far I got with the picture. # 5 is completely missing the bolt head. So I went ahead and ordered a new manifold from rockauto and some O2 sensors since I will be down there anyways. I'm going to get the bolts from the dealership since I read on GMT that the doorman ones come as grade 5 not 8. Looks like I will be having a fun weekend in the near future

[Aries]

I'm going to get the bolts from the dealership since I read on GMT that the doorman ones come as grade 5 not 8.

What size are they exactly? I've searched and can't find that info. I know a machine shop by my work that carry's every size bolt in grade 5, 8 and 10. I may have to pick some up just to have on hand.

[Sugar16]

I'm sure what size they are exactly. We have all kinds of bolts at our shop but I figure that's something I'd just get from the dealer. I'm sure they are relatively inexpensive

[The Roadie]

The ones from GM have an application of high temp loctite already on them. I think I paid $3-4 each. Not too expensive.

[Sugar16]

That was what I figured

[Trail X]

I used the dorman ones, I actually applied anti seize to mine. As I recall, the dorman ones did have the 10.9 stamp on them, but don't hold that as gospel. (You won't find metric grade 8 bolts.)

What's your plan on extracting the broken bolts?

[Sugar16]

From what I found on GMT and with how cheap the bolts from the dealer are that's the route I'll go for that. As far as getting the bolts out, I think I'm going to get the manifold off and then see what there is to work with. One of my buddies at work is going to help me out with it, since extracting is not one of my specialty's. He has a full set up at his garage so that will defiantly help things out a little bit. He mentioned welding a nut to threads if anything is showing but I'm not really sure that's what I want to do.

[Trail X]

I did the nut welding route and I would do it again if I had to. It can be frustrating, but I did mine without removing the head. If you remove the head you'll have a lot more room to work with. I really didn't want to deal with all of the work required to take the head off unless I had exhausted all other alternatives.

[dvanbramer88]

I had a few broken exhaust manifold bolts on my truck. I found similar grade 8 bolts at home depot. Had the same length with a similar sized shoulder. (mine aren't metric) And they have been doing fine.

Also, I run anti-seize on my exhaust manifold bolts like James.

[Moots1288]

The dorman ones are probably 8.8 cause they're metric and 10.9 is equivalent to grade 8 just without the yellow zinc coating.

[Trail X]

Looks 10.9 to me. The dorman package came with 1 extra that's been still floating around my shop.

[Moots1288]

Looks 10.9 to me. The dorman package came with 1 extra that's been still floating around my shop.

well I said probably, going by what to op said. I have never bought a set.

[Sugar16]

Well maybe I will wait until they come in and see what they are. I really don't want to remove the head unless I have absolutely no other way of getting them out