Just a guess but I assume you need 2 sets??? All the bolts are the same size.

 

Yeah something's off. The new header has 9 holes... And I doubt you would need to buy more than one kit.

 

I honestly don't even remember the size and length. It's been a year now since I changed em. I don't even own the Hummer anymore, but as far as I know, it's still going strong.

 

Same studs for multiple applications. You could always just buy 1 kit and reuse 3 bolts.

Correct thread pitch:
03133
Bolt Grade: 10.9 (M10-1.5 X62Mm) And 6 Nuts (M10-1.5)


I always prefer using studs on the manifold, thread the studs securely into the head, and pull the manifold to the head with the nuts. Less chance of crossthreading and you wont "bottom out"!

 

I just checked today HummerZ, and 3 is about all I have left! I just pulled one out, figured 4 are already broken, why not take out one more. I was going to take it to Fastenal or a hardware store tomorrow and get all new ones. But thank you. Those numbers will help greatly at the store. I like the stud idea as well so I'll look for them first.

Thanks everyone.

 

Just a FYI Hummerz, the bolts are not M10s, but M8s. Well, let me clarify, for a 2006, Hummer H3, Adventure package, white with 130k miles on it.... Lol, they are M8s. And there are 9, all the same size.

 

You are correct, they are indeed m8. Many gm sites list the intake manifold and exhaust manifold bolts as the same, however they are different sizes.

BOLT. Intake & Exhaust Manifold. 2006 Hummer H3 # 11588352




Exhaust Manifold: All Technical Service Bulletins
Exhaust System - Ticking Noises

Bulletin No.: 08-06-05-008

Date: October 21, 2008

Subject:
Exhaust Tick Noise, Exhaust Manifold (Replace Gasket, Bolts and Manifold as Necessary)

Models:
2006-2009 HUMMER H3

with 3.5L or 3.7L Engine (VINs 6, E - RPOs L52, LLR)

Condition

Some customers may comment on a tick or noise coming from the exhaust. Upon further inspection, the technician may discover a leaking exhaust
manifold gasket. In some cases the leak may be accompanied by a broken manifold bolt.

Correction



Replace the exhaust manifold gasket and bolts (new part number) following the Exhaust Manifold Replacement procedure listed in SI. Be sure to follow
the torque sequence procedure and tighten the bolts to a MAXIMUM of 20 Nm.

The exhaust manifolds are ductile; they must be allowed to move with heat expansion and cooling contraction. The manifold bolt holes are larger than
the bolts to allow manifold movement. If the bolts are overtightened or torqued unevenly, the manifold movement will be restricted, which may result in manifold cracking or bolt breakage.

In rare cases, the exhaust manifold may also be cracked most likely between exhaust runners # 4 and # 5.

DO NOT replace the exhaust manifold if it is not cracked. Often the exhaust manifold will appear warped when unbolted this condition is NOT a reason
for exhaust manifold replacement.

DO NOT replace the exhaust manifold if a bolt is broken and/or the gasket is leaking.

DO NOT remove the cylinder head to extract a broken exhaust manifold bolt. Follow the bolt extraction procedure found in this bulletin.

Broken Bolt Extraction Procedure:

Important:

Always use penetrating lubricant when removing studs or nuts. Do not exceed 150 rpm tool speed when removing or replacing the three
exhaust flange gasket studs or nuts. The studs are a thread lock design, and damage to the stud or manifold will occur if 150 rpm tool speed is exceeded.

Remove all unbroken manifold bolts and flange nuts.
1. Remove the exhaust manifold.

2. Using a center punch, dimple the center of the broken bolt.

3. Using a right angle air drill and a 5/64 bit, drill a hole through the broken bolt.

4. Spray penetrating lubricant through the drilled hole so that the bolt threads are saturated from the back side.

5. Heat the cylinder head flange area around the bolt.

6. Using a bolt extractor, remove the broken bolt from the head.

 

Well the deed is done. Old manifold is gone, new manifold is firmly attached with (8) M8-1.25s and one M10-1.25 (there's always one that won't cooperate) It was a long process, trial an error in some cases, but I am very happy with the results. I took pictures along the way, so if anyone is interested in a tutorial I'd be happy to post them with some pointers.