Broken Exhaust Manifold Bolt

[mxjunkie123]

does anybody know the size of the bolt it happened on my 04 and was wondering if the different years have different size bolts?

[darkdreamer3]

I ran into the same bolt problem on my 05 avalanche I took off both manifold and lucked out and got all the bolts out but the rear on the drivers side. Put it all back together and man did it leak bad but I found this awesome fix for it that did not involve drilling out the bolt. Dorman makes a bracket that bolts to the back of the head and then runs a bolt into the manifold to put pressure on it. And bam no more leak worked like a charm and only cost me 45 bucks part number is 917-107 if you guys want to look it up

[davester]

Yup, same problem for me. 3 of the 4 end bolts of my '04 6.0L gas motor were broken off. Bought 3 of the dorman kits [they have one for the passenger side rear & drivers side front, and a different one for drivers side rear], and it REALLY helped with engine performance. I also replaced the rest of the bolts with 10.9 flange head SS bolts.

 

Before I did this, the PCM was having problems with keeping the fuel trim within range (+-10%), afterwards, it was much better.

[00Silverado4x4]

So related but unrelated question....

 

Are these bolts breaking because of the difference in metal in the head vs the block/manifold?

I only ask because by time my previous truck ('06 Sierra) was totaled early this year it had 2 broken manifold bolts but my current truck seems to have all bolts intact with 300+k miles on the odometer (6.0L iron block & heads). I know the bolts may have been replaced at one time or another but it's hard to tell by the looks of the bolt heads.

[Formulabruce]

So related but unrelated question....

 

Are these bolts breaking because of the difference in metal in the head vs the block/manifold?

I only ask because by time my previous truck ('06 Sierra) was totaled early this year it had 2 broken manifold bolts but my current truck seems to have all bolts intact with 300+k miles on the odometer (6.0L iron block & heads). I know the bolts may have been replaced at one time or another but it's hard to tell by the looks of the bolt heads.

The bolts are "under engineered'. they are a size smaller than the old reliable 3/8 exhaust manifold bolts. I Always use a 3rd metal never sieze too. I use Copper" never sieze on aluminum, not the standard aluminum stuff. I use a grade 8+ bolt M8 . I need to have one fixed on my drivers side rear and Im thinking the head will have to come off as its broken off inside ( manifold been replaced) . This is the biggest problem with the LS engines IMHO