Well we just purchased this h3 this summer and maybe do to our excitement i never noticed the exhaust noise but sure enough it turned out that 3 back bolts had sheared off. I have seen previous posts of this happening and thought how bad could it be.
So to access the bolts you need to remove airbox, to give you the room required to remove the heat shield as you can see in the photos. Be ready to take some time as to avoid breaking the existing manifold bolts off when removing them. I soaked every bolt with pb blaster numerous times before doing the actual job.
I can tell you that with some effort this can be done if you have the proper tools and ability to slow down and not rush the job.All hand tools were used on motor and the air ratchet was only used after the exhaust bolts were heated up and verified that they would come off without breaking.
Well as luck would have it all 3 back bolts were broken flush with the block as seen in photos. This was a genuine oh **** moment, The 2nd of the 3 was actually broken off inside the block.

 

So i purchased the required exhaust gasket and stud set and began the task of removing the existing broken bolts. To get the two outside bolts i used a extractor set and you need to drill into the center of the broken bolt and use heat to expand the block area to assist in removing the bolts plus a trick i learned a long time ago is to heat area not the bolt itself and take a candle and put on bolt, the wax will melt and suck into the threads as it cools.
I heated up the area after drilling and sprayed more pb then slowly extracted the 2 outside bolts.This job takes patience and i walked away more than a few times to get my game plan together. Remember that the extractors can and will break if not used correctly.

 

So after some more heat the outside bolts did come out.This job did take me the better part of two days because i did not want to break off taps in drilled bolts.
Some of the tools needed are in the pictures but your needs may be different.Also not in pictures is a magnetic pickup tool as you will most likely drop something and it becomes your third hand.
Now onto the middle bolt,It was snapped about a quarter of a inch inside and i tried the drill and tap , wax,pb blaster and the damn thing was not coming out so this is where you better take some time to think thru what has to be done to get it out. So my only choice now is to drill it out and that is why you need to take measurements of hole depth and mark your drill bit so as not to hit water jackets etc... by drilling to far.

I started by using a small bit and increasing the size to just under the original 8mm hole

 

After i was done drilling it was now time to use a 8mm tap and rethread the block to correct size. Again i will say do not use power tools as you will break the tap and not be a happy camper.

This is where you need to slow down and go slow as you cut threads in the existing block you need to use cutting fluid and remove the tap at different stages to clean out cut threads and cutting material.As you can see all was successful and for 40 dollars in materials made me a happy camper. All the new studs were coated with anti seize and the one stud that was retreaded was installed with locktite.

Hopefully you will have some stud material sticking out but as with my luck this was not the case and a quote of 700 plus to repair was not an option.I hope this gives you an idea on how to repair this common problem

 

No room for a helicoil?

 

Thank you for taking the time to write up these important pointers, with pics, on getting such a miserable job done.

KUDOS!

 

Yes, thank you.

Chris

 

Yes i did purchase a heli coil set but wanted to use that as a last resort. I know they have proven themselves time and time again but they also have pulled out on occasion. Now if in the future the current bolt fails i will use it but i wanted to limit the size of the hole .

 

Thanks for the kudos, I am glad to help if i can and just as glad its done

 

Ok extremely rookie here, so I have a question.

How can I tell if mine has this issue? Will I need to remove the heat shield and look for a gap of some sort?
Will the sound be very noticeable?