4.0L Intake Manifold/Cylinder Head Carbon deposits | Ford Explorer Forums - Serious Explorations

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4.0L Intake Manifold/Cylinder Head Carbon deposits


Well-Known Member
November 25, 2009
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Year, Model & Trim Level
'04 XLT
Doing the dreaded death rattle fix (timing chain guide replacement) and have noticed the intake manifold and cylinder head intakes are covered in a film of what appears to be carbon.

Does this indicate another or a more serious issue?

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No your fine it's normal the egr system re-Circulates the exhaust gasses back into the intake

Agree with Donalds. I cleaned mine off with Seafoam--especially around the valves. Take the time to do your throttle body (not EGR related, obviously) at the same time!

Thanks for the suggestion. I did replace the Throttle Body a year ago for codes but since it's off now will be a good time to clean it.