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Put in some new AEM dryflow air filters and had to deal with the "post" air filters. So after I ripped all the stuff out I noticed some strange cracks but I'm hoping its just some casting flaws but looks bad. No CEL's and it runs and drives fine. Has anyone see this on their V8 intake manifold???
BTW I have a 2007 SLK55 AMG M113 V8
Pictures below.
 

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Registered 2005 SLK55 AMG
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Looks quite alarming. Even if it's not causing a fault, it doesn't say much for Mercedes/AMG engineering. At least we now know the reason for plastic engine covers.
 

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Registered 2005 SLK55 AMG
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Sand Cast Magnesium

SLK AMG 55 intake manifold is made of magnesium and if you look at the overall finish you'll note is wasn't die cast but rather sand cast. What I see when I look at the images is that some loose sand was left in the die after the pattern was removed. If those were in fact cracks you would be getting codes from a vacuum leak. Mercedes likely went with magnesium for weight reduction and didn't use plastic as they do on production models due to the tendency for it to dry out and become brittle over time. I wouldn't be really concerned but if you are, start the engine and spray some carburetor cleaner where you suspect you have a crack, if you do you'll note am immediate change in the idle of the vehicle. For anyone interested I posted a video of the sand casing process, I'm sure MB does something close to this in the making of our manifolds but probably a bit lacking on the QC side of things with the obvious casting defects cause by not removing all the sand from deep crevasses after the pattern was removed.

As you can see from the image, sand casting is hardly a tidy process or something the average person would want to do for eight hours a day. Relax, I think you're OK.:nerd:

Magnesium is 33% lighter than aluminum, 60% lighter than titanium, and 75% lighter than steel. Yet for many applications it's stronger per unit volume than all three of those structural metals. Remember the old term "Mag" wheels? yep those were made of magnesium as well, just a bit more polished and in some cases plated.

 

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Registered 2005 SLK55 AMG
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This defect in this image is quite obviously a casting defect cause by leftover sand in the mold. It probably passed x-ray but should have been rejected by the builder on visual inspection for aesthetic reasons. Shoot your carburetor cleaner there, if there isn't a vacuum leak there you don't have one. and I doubt you do.
 

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Registered 2005 SLK55 AMG
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509 Posts
Put in some new AEM dryflow air filters and had to deal with the "post" air filters. So after I ripped all the stuff out I noticed some strange cracks but I'm hoping its just some casting flaws but looks bad. No CEL's and it runs and drives fine. Has anyone see this on their V8 intake manifold???
BTW I have a 2007 SLK55 AMG M113 V8
Pictures below.
When you say you had to "deal" with the post air filters what do you mean? The PO on my car had removed them and I put them back in. Keep in mind your cylinder bores are lined with silicon/aluminum which is basically a ceramic, anything that gets by the air filter and trapped between the piston clearance and cylinder would be bad, very bad in terms of the damage it might inflict. AEM makes a good product but I'm not sure I trust their 99% claim on harmful contaminant, leaving the OEM filters in is like wearing a belt with suspenders and unless you're racing someone for the deed on your home anything you might give up in performance is made of for with peace of mind.
 
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