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11-23-2011, 10:51 PM
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Hummer Veteran
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Join Date: Nov 2011
Posts: 101
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Re: Exhaust Gasket leak and stud broke
Ok, I was able to take the broken bolt out with a pair of vise grips.
After that I put the new studs, and I re-used the same gasket because the only ones I could find for sale that would ship to my country were Felpro, and I heard a lot of mixed feedback, so I just re-used the gaskets.
I tightened all the bolts a first pass to 11lbs, and a second to 18lbs, like in the manual.
I noticed that where the broken bolt was, with the new bolt tightened to 18lbs, the header was still not even making contact with the manifold, so I had to tighten it really hard to get it to make contact. (It probably stayed a lot of time with the bolt broken, so it got bent out of shape)
Then, I connected the spark plug wires, and turned on the engine, but the noise is still there, A LOT more quieter now, but it's still leaking air, I can hear it.
Now, I don't know what I should do, if I should tighten all the bolts a little bit more, especially the one where the broken one was, or maybe it can be a leak from the gasket, although I don't think so.
What do you think, should I tighten the bolts a little bit more tomorrow?
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11-23-2011, 11:13 PM
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Hummer Authority
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Join Date: Oct 2003
Posts: 1,118
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Re: Exhaust Gasket leak and stud broke
I had to double checked the torque specs and you do have them correct but while looking at the manual it did say not to use the old gaskets. I am afraid it may be the gasket that is the problem now
I would hate to see you tighten the bolts more than the 18 foot pounds and either strip out the threads in the head or break another head of a bolt off.
The call is yours and I know it is not cheap to get the gaskets sent to Portugal but I would get the new ones and do it right and hope for the best
Good luck, Ed
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11-23-2011, 11:29 PM
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Hummer Veteran
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Join Date: Nov 2011
Posts: 101
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Re: Exhaust Gasket leak and stud broke
At least the last bolt will have to be tightened at more than 18lbs, because like I said, at 18lbs, there was still a gap between the header and the manifold on that one... The only bolt I have overtightened now, is that last one, that is on the place of the broken one... Maybe if I tighten that one a little bit more, it will stop making the sound, I don't know
I'm thinking like that because, if there was a gap at 18lbs, then maybe I haven't fully closed it at the torque I have on it right now, maybe a little more would close it good.
I'm afraid that it will brake with time, but if I don't overtighten that bolt, then I have a big gap that lets all the air out...
Last edited by cashville : 11-23-2011 at 11:31 PM.
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11-23-2011, 11:43 PM
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Hummer Authority
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Join Date: Oct 2003
Posts: 1,118
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Re: Exhaust Gasket leak and stud broke
The bolt should handle the extra torque because of the grade it is, guess it is worth a try.
Edit: max torque dry looks to be 24 to 27 foot pounds for a 8 mm 10.9 grade.
Good luck, Ed
Last edited by Easy Ed : 11-23-2011 at 11:48 PM.
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11-24-2011, 12:06 AM
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Hummer Veteran
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Join Date: Nov 2011
Posts: 101
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Re: Exhaust Gasket leak and stud broke
I'm not even sure at how much torque the last bolt is, because it's the only bolt with bad access, and my torque wrench wouldn't fit in that place. After the others I could get a feeling of the 18lbs, and put it around that, and I did but it was not enough to close the gap. After that I tightened it a lot, because a lot was needed for the header to go back into place with no gaps.
What I'm thinking of doing tomorrow, is do a leak test and spray some wd40 around the manifold (will start with the place where the broken bolt was), and see if I get a different engine idle, just to detect the leak and make sure it's really coming from that place.
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11-24-2011, 02:23 AM
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Hummer Veteran
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Join Date: Nov 2011
Posts: 101
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Re: Exhaust Gasket leak and stud broke
I couldn't wait till tomorrow, so I tightened the last bolt as much as I could, and turned on the engine. the noise was still there, so that didn't help. I then sprayed wd40, and noticed bubbling coming from the gasket at that last bolt. I turned off the engine, and unscrewed the last bolt a little, to not leave it there overtightened.
So, I guess I'm investing in a Felpro gasket. Lol.
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11-24-2011, 05:02 AM
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Hummer Veteran
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Join Date: Nov 2011
Posts: 101
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Re: Exhaust Gasket leak and stud broke
btw, I didn't put anything on the used gasket, I just took it out, and put it on again. Should I have used a sealant or something?
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