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Danger Zone for Exhaust Manifold Bolts

Geoff Wilson
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Geoff Wilson New Member

Geoff Wilson

Posted
Posted

I have been hearing around the nets that broken Exhaust Manifold Bolts are a thing for the GM5.3.  So much a thing that there are kits sold on Amazon that will tighten the exhaust manifold to your block after a few bolts have broken their heads off.  The removal of these broken bolts, I hear, is a sucky job.

 

So, in that spirit, and because it was a nice day, I invested in a 10 dollar bag of exhaust manifold bolts and changed mine preventatively (I have 108,000 kms on my 2013 Sierra1500SLE).  The old ones had rusted heads, and when I pulled them out they put up a bit of a fight (most of it was getting leverage angles on the right ratchets/wrenches), but otherwise I didn't see any obvious warning signs.

 

So this begs the question: when are these bolts in danger of breaking off?  Anyone had any experience with this?

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CamGTP Senior Enthusiast

CamGTP

Posted
Posted

Hard to say how close they were. They can honestly look just fine on the outside but they will pop the head of the bolt off anyway. It's usually always the outer most bolts that do it first. Seens trucks with higher miles and only 6-7 years old with missing bolt heads.

 

For as cheap as they are, it's good that you did replace them.

shakenfake Senior Enthusiast

shakenfake

Posted
Posted

My 1999 5.3 had no bolts break when I pulled the manifolds off. The 04 LQ4 I put in my truck had 4 broken off, two on each head if I remember correctly. 99 - 220k miles. '04 - 134k miles.

dna9656 Enthusiast

dna9656

Posted
Posted

So far as I'm concerned all head bolts are a chancy thing to remove due to the corrosion and heat issues. Standard advice always applies to head bolts: Soak them in penetrating oil for days before hand, apply torque to each bolt after much prayer and meditation, hope for the best but be prepared to have to remove the head to remove broken bolts. This is why a lot of people don't run headers, it's a chancy thing that you'll get it done without broken bolts and a huge job to fix them. 

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txab Senior Enthusiast

txab

Posted
Posted

I've used heat on them to break the thread locker. They come out easily. Never broke one taking it out. Seen many already broken

Bleepster Enthusiast

Bleepster

Posted
Posted

I have a 2011 5.3 - driver side front bolt is broke - all on its own.  the amazon kit I believe is for the back bolts only.  i refuse to pay over $600 to get my bolt fixed.

dna9656 Enthusiast

dna9656

Posted
Posted

$600.00 is insane, a right angle drill would be a good investment for this job as it will certainly pay for it self the first time you use it. If you're lucky you can reach it. Pulling the head on a 5.3 is an expensive thing to do, according to GM you have use a lot of new parts, it's not just a head and intake gasket anymore.

I was overseas when a guy in the shop pulled a head on a Ford V 8 leaving the intake in place and he just cleaned it all up and put in a new head and intake gasket, saved a lot of time and labor...

txab Senior Enthusiast

txab

Posted
Posted
3 hours ago, Bleepster said:

I have a 2011 5.3 - driver side front bolt is broke - all on its own.  the amazon kit I believe is for the back bolts only.  i refuse to pay over $600 to get my bolt fixed.

Weld a nut on it and unscrew it. It's really the best way to go

dna9656 Enthusiast

dna9656

Posted
Posted
21 hours ago, txab said:

Weld a nut on it and unscrew it. It's really the best way to go

That works if the bolt didn't shear off below the plane of the manifold down in the hole.

I have never had that kind of luck!

txab Senior Enthusiast

txab

Posted
Posted

It works even if it's below the surface of the head. Done it many times. Most shear off just below flush. Plenty of videos out there showing the procedure

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

He's saying the manifold is still on the truck. He'd have to take the manifold off first then weld the nut on if you couldn't grab it with vise grips.

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