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Carbon buildup in intake manifold

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Good day everyone,

Today i was cleaning the cai and the throttle body on my boss and when i removed the throttle body i noticed black carbon soot in the walls of the intake manifold ... not a noticeable thick pile but when i put my finger in my finger was totally black.

Please advice if it is normal or should i remove the intake manifold and get it cleaned ?? My mechanic says that its normal and won't affect performance neither affect smoothness of the engine... so i just raised this point for our expert collegues for advice.

Thanks,
 
141
153
Exp. Type
HPDE
Exp. Level
5-10 Years
Arizona
It’s just oil residue from the PCV system. Yeah it’s pretty much harmless. An oil separator on the passenger side can help reduce the amount of oil vapor going through the intake. Oil can reduce the knock resistance of your fuel if you get enough in the intake. I doubt you are at that point.
 
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8,187
nothing to worry about, back in the old days it was usually caused by valve overlap on extremely high RPM camshafts. Today, not so much, usually the PCV as mentioned.
 

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