I gotta go into the shop this morning to pull the left exhaust manifold. The rear bolt head is broken off. I'm not sure why but the head of it is just gone now causing an annoying exhaust leak until it gets warm and expands.

I went into the dealership to pick up a couple of gaskets and replacement bolts. (THAT's how I ended up buying that damn light bar... shoulda never walked into a place that sells "stuff")

Anyway, talking to a tech there, he mentioned he has replaced a few of them for the same thing.

Anyone ever heard of that? I'm just hoping like hell when I pull the manifold, the remaining stud that is sticking out doesn't break off flush.

Mark

I gotta go into the shop this morning to pull the left exhaust manifold. The rear bolt head is broken off. I'm not sure why but the head of it is just gone now causing an annoying exhaust leak until it gets warm and expands.

I went into the dealership to pick up a couple of gaskets and replacement bolts. (THAT's how I ended up buying that damn light bar... shoulda never walked into a place that sells "stuff")

Anyway, talking to a tech there, he mentioned he has replaced a few of them for the same thing.

Anyone ever heard of that? I'm just hoping like hell when I pull the manifold, the remaining stud that is sticking out doesn't break off flush.

Mark

Got it done... took about 2 hours. Pretty simple, just time consuming spinning what's left of the broken bolt with a pair of visegrips.

take the wheel off and remove fender liner.




Undo the 6 bolts holding on the exhaust manifold. You can reach them through the inner fender. I also undid the 3 bolts connecting the exhaust manifold to the exhaust pipe. (this will allow you to slide the manifold to one side out of the way)




Though not a great pic, the bolt you see is the one closest to the firewall. The head was simply missing.



Here's the culprit... little bastage

Re: Exhaust manifold bolt breaking?
 

Both my exhaust manifolds had the rear bolt head broke off. Unsure what is causing this but its not just on the hummers, the chevy garage had a tahoe in there with same rear bolt broke off.

Mechanic did same as you used vise grips to unscrew the stud (rest of bolt-head= stud) out.

If you hear an exhaust tick be assured its a broke bolt-
Chris

Re: Exhaust manifold bolt breaking?
 

Just had the same thing happen to me with my exhaust manifold bolt(s).
I have 79K on my 04 and started hearing a sound like air escaping on
start-up. After some time the sound goes away. Upon inspection I found that my
exhaust manifold bolt had completly snapped off and only a small
part of the treads remain.

I located the bolts at a local fastenal dealer - here is the link for anyone interested.

http://www.fastenal.com/web/products...1115929&ucst=t

These are Grade 90 bolts but you can also get the 10.9 Grade but since I
am going to all of the trouble to replace them...........for $18 who cares.
I would rather use Grade 90 and be done with it.

Appearently this is a common problem with H2s. Little did I know.

Re: Exhaust manifold bolt breaking?
 

i had this problem somewhere about the 70k mark for my H2.
i had done alot of research prior to that and recognized right away what the issue was when it happened.

my H2 was still under the extended warranty then, so had no problems, but i imagine it will pop its head again at some point unless they used higher quality bolts.. and if they did, i doubt they repalced all of them on both sides.

Re: Exhaust manifold bolt breaking?
 

at about 48,000 my 2004 went in to replace the power steering pump and idler and pitman arms. They noticed that there were 2 broken ex manifold bolts. I had never heard any hissing or other sounds indicating a manifold leak and I'm not sure which bolts they were. But in order to extract one of them they had to pull the head to get a straight shot at it. Luckily I still was under extended warranty, but the truck was in the shop for a week.

Re: Exhaust manifold bolt breaking?
 

It happened to me as well i have 150,000 miles on her.
I have replaced:
Exhaust manifold bolts
Catalytic Converters
Radiator
Altenator
Battery
Serpintine Belt

I love this truck

Re: Exhaust manifold bolt breaking?
 

There was a Technical service bulletin on this. They changed the bolt spec because of this problem. The new bolts have a larger head .

Re: Exhaust manifold bolt breaking?
 

Do you know when they made this change? Just wondering if this is something I should be watching on my 2005.

Re: Exhaust manifold bolt breaking?
 

I dont have the bulliten anymore, maybe somebody else does.

Look at the heads on your bolts, then go to the dealer and look at the heads on the replacement bolts. If the new bolts have larger heads then whats on your h2, you need to change them.

Re: Exhaust manifold bolt breaking?
 

I had 2 broken on the right side and 2 broken on the left. The left rear was broken below the surface and it took me a few hours to drill it out and extract it. The other 3 had exposed studs that i ground 2 flats on and used a wrench to get them out. Screw the cheap GM bolts! I installed a set of hardened studs that will never break!

After all of that was done I installed a set of OBX Stainless Long Tubes, stainless high flow cats and stainless all the way out the back. Sounds great, pulls hard and i couldn't be happier!!!

Later,
AO

Re: Exhaust manifold bolt breaking?
 

Been there, done this on my ride not too long ago. After breaking several types of bits on trying to drill it out and tap it out, had to pull it and have the bolt melted out and had the hole rethreaded by a fabrication machinist. This one really pissed me off, pretty dissappointed in GM for this one...:rant:

Re: Exhaust manifold bolt breaking?
 

How long have you had those headers on now? I think you can buy those on Ebay right?

Thanks

Re: Exhaust manifold bolt breaking?
 

Been on for 1-1/2 months now and all is well. Yes got them on Ebay.
AO

Re: Exhaust manifold bolt breaking?
 

Any suggestions on what's the best replacement for the bolts?

Re: Exhaust manifold bolt breaking?
 

Someone else posted these a while back:
http://www.fastenal.com/web/products...1115929&ucst=t

I just installed them

Re: Exhaust manifold bolt breaking?
 

I installed them as well. They haven't backed out and it's been a couple months.

Re: Exhaust manifold bolt breaking?
 

well I've been fighting a case of procrastination on this very issue for months. In part because I was on the fence on trading the truck in. I finally fell off that fence on to the right side :)

Anyway I was originally going to go the route PDX took but after some thought I think I want to avoid the long tube headers and probable need for tune and such. I am now looking at this OBX header solution, http://www.ebay.com/itm/OBX-Exhaust-..._2735 wt_1145

I am assuming this are a direct swap with perhaps some very minor benefit but likely better then replacing with stock manifolds which surely will rust to crap in short order. Mine are shot and will need to be replaced.

Question I have is NO EGR is correct for 2003 H2, also anyone have experience with short headers and any thoughts.

Also looks like those Fastenal bolts are out of stock completely. Ordered and hoping its not a big issue but if it is any thoughts on the updated stock bolts which I suppose I could get from the stealership.

Re: Exhaust manifold bolt breaking?
 

To be clear, I did not need a tune as a result of the LT headers. Not at all.

Call a local Fastenal and ask them to order them in for you. That worked for me for whatever reason.

I don't have much info on the short tubes a side from what you've already mentioned.