Well, that's a first (intake manifold failure)
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2011 C63 AMG P31
Well, that's a first (intake manifold failure)
I've never seen or heard of this before on a C63! Failing gaskets is one thing... But to have one of the bolt heads sheer right off? All the others were very loose as well.
My guess is the bolt was poorly made, and backfiring into the manifold increased the pressure enough to blow the already weakened bolt apart. I'm guessing that backfiring into the manifold was caused by my mountain run this weekend, rapidly changing elevation in my mind could have caused a series of non stoichiometric cycles .
Anyone else has this happen?
This has solved the myriad of issues my C63 has been encountering though, so in the end I'm happy b
Last edited by ToXicXxX; 10-29-2014 at 11:02 PM.
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2011 C63 AMG P31
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2011 C63 AMG P31
No problem. When you check yours, do not try to tighten them, just see if they are loose or broken.
I doubt anyone else has broken bolts, I haven't heard of the problem until it hit me.
I doubt anyone else has broken bolts, I haven't heard of the problem until it hit me.
#6
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Wow thats crazy,
Looks like an over torqued bolt.
How did you find out? Any symptoms?
Looks like an over torqued bolt.
How did you find out? Any symptoms?
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#8
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It's like headbolts. There is a certain way to tighten bolts. It stretches the bolt to the torque to yield and also spreads out the pressure on the gasket equally.... Something along those lines I believe.
waiting for Ingeniuer to chime in with his formulas and theories.
waiting for Ingeniuer to chime in with his formulas and theories.
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2011 C63 AMG P31
I was also smelling combustion somewhat under the hood. Tested all my header bolts, they are still very tight with no evidence of gas escape.
The issue started occurring on a hard mountain run in Montana, then the codes cleared for a bit, and permanently came back after a drive to Red Deer. When I got to the shop the next day I started all sorts of testing. My idle is also somewhat erratic, it doesn't hold an RPM value but instead bounces around softly.
Bolt and gasket replacement will be done tomorrow. I'll report the results.
Looking at the end of the broken bolt, it doesn't have a pattern consistent with torsion forces, but instead looks like it was torn apart.
Last edited by ToXicXxX; 10-30-2014 at 01:12 AM.
#13
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I second this notion!
The reason I think this is true is that the pressure loads on the intake manifold bolts are very low. However, the torque loads during installation are extremely high since these are torque to yield bolts.
The reason I think this is true is that the pressure loads on the intake manifold bolts are very low. However, the torque loads during installation are extremely high since these are torque to yield bolts.
Last edited by glennhl; 10-30-2014 at 01:10 PM.
#14
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Did you remove the intake manifold to get to your header bolts?
I know you recently installed your own headers, perhaps the bolts were torqued incorrectly after re-install?
I know you recently installed your own headers, perhaps the bolts were torqued incorrectly after re-install?
#15
I've had my Intake Manifold replaced by MB warranty with similar symptoms. When I asked the SA what it was they said they found it had a crack leaking pressure, but didn't mention anything about the loose bolt. I thought the problem was perhaps from the last owner of the car and maybe the CPO inspections missed this when I purchased it.
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c63
As mentioned above, I think what happened was the garage I used hasn't worked on benzes and they basically didn't properly install it. Car went into limp mode 2-3 weeks after headers were installed.. Took it back to the shop they apparently got a quick fix for it as it came back couple months later. All in all I learned to not go to garages based on what cars they work on rather look for a specialist which I found in Austin in another shop. I would say you shouldn't worry unless you doubt who installed ur upgrades if any.
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2011 C63 AMG P31
Nope. Didn't remove anything to install them, was done from the bottom up. I am also an AST (I work for a European tuning shop).
Gaskets and bolts fixed the lean issues. The gaskets were wrecked... 38,000km on them and they were severely blackened.