Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: mopars4ever]
#3094362
11/15/22 01:25 PM
11/15/22 01:25 PM
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Joined: Jan 2006
Posts: 2,386 White Plains, NY
VCODE
top fuel
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top fuel
Joined: Jan 2006
Posts: 2,386
White Plains, NY
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I had the same problem on my 2004 Ram 2500 5.7. I replaced all the bolts and had the manifold machined. So far so good it's been about 2 years. They all do it. Cheap China Casting I guess.
Last edited by VCODE; 11/15/22 01:25 PM.
Mom & Dad let me buy a brand new 70 Challenger R/T 440 Six-Pack Super Trac Pack when I was 17
(Robert what is a 440 Six-Pack)
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: VCODE]
#3094366
11/15/22 01:32 PM
11/15/22 01:32 PM
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Joined: Dec 2014
Posts: 5,924 ohio
ruderunner
master
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master
Joined: Dec 2014
Posts: 5,924
ohio
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I'm thinking more environmental. You 2 as well as I are in the rust belt/ snow belt area of the country. I have replaced manifolds on several brands of trucks and the common factor is rust. Ford manifolds will actually rust through but all suffer rusted bolts, rusted castings. The castings cause "rust jacking " where they expand under the bolt and pop the heads off.
Anyone from a rust free area have broken bolts?
Angry white pureblood male
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: ruderunner]
#3094370
11/15/22 01:41 PM
11/15/22 01:41 PM
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Joined: Jan 2003
Posts: 13,382 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,382
Marion, South Carolina [><]
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It happens down here too. Had a friend w/ a 5.7 hemi that kept breaking exhaust manifold bolts. This was over 10 years ago.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: mopars4ever]
#3094415
11/15/22 04:03 PM
11/15/22 04:03 PM
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Joined: Jan 2003
Posts: 17,904 S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,904
S.E. Michigan
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This is why, many of the older guys in the industry like my Dad, when OEMs started to change to metric in the late 70s, fought it tooth and nail and complained to the powers that be.
Because his associates and he knew the finer increments of metric fasteners would allow Engineering to eventually reduce mass and cost to the point vehicles would make it to 3-36, and after that...."hey, who cares? Make money from parts and service! Not our problem anymore".
This is what we have to work with....Iron manifold, aluminum head, tiny metric fasteners. Think about expansion/contraction, hot/cold, over and over. It's just a [censored] combination.
If those fasteners were 3/8" grade 5 or 8, think they'd still break?
Rich H.
Esse Quam Videri
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: mopars4ever]
#3094428
11/15/22 05:08 PM
11/15/22 05:08 PM
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Joined: Jan 2005
Posts: 12,422 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
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Posts: 12,422
Kalispell Mt.
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Aluminum head, iron manifold expand and contract at different rates and highly stresses the tiny bolts and most of the time it is the end bolts that break because that is where the most difference in expansion and contraction is experienced by the head and manifold.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: HotRodDave]
#3094437
11/15/22 05:47 PM
11/15/22 05:47 PM
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Joined: May 2019
Posts: 6,306 nowhere
Sniper
master
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master
Joined: May 2019
Posts: 6,306
nowhere
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Aluminum head, iron manifold expand and contract at different rates and highly stresses the tiny bolts and most of the time it is the end bolts that break because that is where the most difference in expansion and contraction is experienced by the head and manifold. Yep, the manifold is expanding in length when hot, contracting as it cools. That wiggles the bolt back and forth breaking them. Funny thing is, Chrysler knew the solution, look at any flat head six, or slant six and you will see that was done to keep those long exhaust manifold from cracking or breaking studs.
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: poorboy]
#3094543
11/16/22 12:48 AM
11/16/22 12:48 AM
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Joined: Jan 2003
Posts: 20,204 Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,204
Park Forest, IL
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Slant used low torque on the nuts too. 10 ft. lbs.
"Everybody funny, now you funny too."
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: slantzilla]
#3094557
11/16/22 02:15 AM
11/16/22 02:15 AM
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Joined: Jan 2003
Posts: 8,403 Highland, MI.
Sunroofcuda
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master
Joined: Jan 2003
Posts: 8,403
Highland, MI.
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Are the manifold bolts stainless? If so, you can't harden stainless. They need to be grade 8.
No Man With A Good Car Needs To Be Justified
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: 360view]
#3094582
11/16/22 08:40 AM
11/16/22 08:40 AM
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Joined: Jan 2007
Posts: 10,156 A Red State
SNK-EYZ
I Live Here
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I Live Here
Joined: Jan 2007
Posts: 10,156
A Red State
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When I was working a repair station on the assembly line in the chassis department I told an engineer of a problem with a part that they had changed and the exact words of the engineer were "As long as it makes it out of warranty, we just don't care"..........
Kayse can't keep up at all now. lol
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Re: What is causing exhaust manifold bolts to break on the 5.7?
[Re: SNK-EYZ]
#3094620
11/16/22 11:58 AM
11/16/22 11:58 AM
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Joined: Jan 2003
Posts: 13,607 md
mopars4ever
OP
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OP
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md
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Are the manifold bolts stainless? If so, you can't harden stainless. They need to be grade 8.
They were all oem bolts but I found out two bolts on the right side ( the ones that broke) were OEM stainless. I found out when I ordered new bolts and there was two different part numbers for that side. No idea why only those two. The left side were all regular Oem steel but three broke on that side also. I was asking about the manifold because the mopar dealer said the manifolds were on nationwide back order due to a new part number being released so I was hoping it was a change in the manifold design in some way that would help the issue.
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