I own a 2012 Ford F-250 with the 6.7 liter Powerstroke Turbo Diesel with 152,000 miles. I bought the truck when new and it has not been modified in any way. Factory original. I recently changed the vacuum line to the turbo due to a buzzing noise on the engine after shutting the key off. The service manager at my Ford dealer produced a service bulletin on the noise back in 2013. To change the vacuum line you must remove the throttle body. What I discovered on my truck was a significant accumulation of soft black carbon immediately downstream of the throttle body for about two inches in length. The engine has never used any oil. So I have numerous questions. Where did the carbon come from? Do I have a problem that I need to address? Is this a harmful development on this engine or is it “normal”? Should I clean this out more frequently? The truck has always run very well, produces great fuel mileage and continues to perform as good as new. When I asked the service manager about this, he would not make any comments on the condition. Has anyone got any information on how to deal with the soft carbon buildup problem?
the carbon is from the EGR valve and the PCV valve.
A can of Seafoam top engine cleaner will get rid of the carbon.