While under my rig I noticed 1 of the exhaust studs broken where the exhaust pipe bolts to the manifold. Knowing there is a problem with the oe manifold bolts to the head I decided to pull the exhaust manifold.

Original bolts to the head are class 9.8 rating, I'm upgrading to class 12.9 rating studs

First I ordered the parts (from ebay)

VICTOR REINZ Exhaust Manifold Gasket MS19755 $10.99
VICTOR REINZ Exhaust Ring Gasket Victor F32146 $9.45
DORMAN 03142 Exhaust Manifold Stud and Nut $6.00
9 M8 x 1.25mm High Tensile Alloy Steel Exhaust Manifold Stud Kit $20.00

$46.44 TOTAL COST

The Seller Accepted $20.00 Shipped, For The Stud & Nut Kit:

9 Piece M8 x 1 25mm High Tensile Alloy Steel Extended Exhaust Manifold Stud Kit | eBay







Designed for extreme and high temperature applications where failure is not an option!

Obsidian 9 Piece Kit Includes
• Nine Obsidian manifold studs (Class 12.9 alloy steel; M8 x 1.25mm x 45mm)
• Nine Obsidian nuts (Class 10.9 alloy steel; M8 x 1.25mm)
• One 2 gram pouch Loctite C5-A Copper Anti Seize
• Easy to follow instructions


Features:
With a class 12.9 rating and a minimum tensile strength of 1220N/mm2 (176,000+ PSI), these extended studs will blow your mind and surprisingly not your wallet!

Just like our popular InoX stainless studs, these feature a 4mm hex drive in the tip which allows installation with nothing more than a mere Allen wrench, how cool is that?

Each Obsidian stud measures 45mm long to allow fitment of aftermarket exhaust manifolds (especially turbo manifolds) and headers that may have a thicker than OEM flange.
On your intake side, these studs will allow for proper installation of heat shielding gaskets like Hondata, Golden Eagle, Bisimoto, and others as these gaskets are much thicker than OEM and can cause fitment issues.

The nuts are crafted with a built in washer that has serrations on the bottom to resist loosening due to vibrations. This built in washer provides the nuts with a larger surface area for greater clamping pressure to insure a tight fit between your manifold or header and your cylinder head. Better clamping pressure insures a tight and leak free fit for years to come and extended gasket life.

Why only a class 10.9 nut, why not a 12.9 or higher?
This is a question that we've been asked on several occasions. By using a lower class nut on the higher class stud, this insusures that in the event the nut needs to be removed or is over torqued by accident, the threads on the nut will be damaged, not the stud. A damaged nut is easier, faster, and cheaper to replace than a stud. We've put a lot of time and thought into the design and development of our kits and we believe it shows!

 

Jumped in this morning & 2 hours later the manifold is removed:

I only found 1 broken bolt on the head (still sticking out and came out easy)





The broken bolt was the rear 1, as you can see in this picture, the exhaust was leaking, although it didn't appear loud?





Back to work, going to do some cleaning and remove some carbon..

 

Nice upgrade project. I figure many of us will eventually face this problem, or the cracked exhaust manifold problem as well.

Thanks for taking the time to give out pointers.

 

Nice write up, thank you!
BTW, with the manifold off will you be porting it?

 

Actually the engine is quieter now. That was fun.
All I did to the manifold was resurface it where it mounts to the head, and remove the broken stud.

 

Nice write up hummerz.

 

nice pics i need to do the same as mine appears to be louder on a cold start ups, then gets quite after it runs a short time. hope i get lucky like you and no drilling required

 

hummerz, awesome information here. As a young man with very little mechanic skills and even less loose change to pay for repairs, I've been saved by this forum.

Now onto the main point, lol. Is this difficult to do? Could I do this replacement at home ? Could you provide information on removal ? I have the manual but reading it isn't my best qualities. ��

Do broken exhaust studs have any effect on fuel economy?

 

Sure, I replaced mine in my backyard.

The most time consuming part was removed the exhaust system from the manifold. I used a MAP gas torch, took some time to heat the nuts red so I could remove them without breaking the studs(1 stud was previously broken), also time consuming drilling and extracting the broken stud from the manifold.

Other than that, quick and easy.

Disconnect both 02's 1 access through passenger side wheel well, 1 up top.

Remove the front wheels, put 4x4's under the lower ball joints nuts and lower the jack on to the 4x4's.
Remove the complete CAI and air filter box, disconect air filter box hose, disconnect maf, 5bolts, losen 4 clamps, and pcv hose. set aside
Remove secondary AIR check valve, 1 connector, 1 hose, 1 nut & 2 bolts. set aside
Remove transmission dipstick and tube, set aside
Remove the exhaust manifold heat shield 1 nut & 2 bolts. push s1 02 wire/connector through shield hole, pull shield and set aside
That's it, you now have clear access to the 9 exhaust manifold bolts.
Crack the bolts lose, then back and forth a little at a time, then back them out all the way.
Careful pulling the manifold out, pushing the heater hoses and ac line out of the way while removing and careful not to damage the o2 sensors/wiring while removing.
Now clean the head and manifold mounting surfaces.

Torque is 15ft lbs
Tighten the bolts pass in sequence (repeat 3 times):



Reinstall everything and reconnect all the connectors. GL

 

Great right up. And thank you, I really should start printing these fix it post, and keep a paper file in the garage.