oil under plenum

[mansopoor]

I'll start with the vacuum problem. I lost the 4X4 and the vent directions so I started looking at my vacuums line. The first problem is some sort of black thing that connects the PVC valve to the plenum, someone teed the vacuum line into it (see pic). Next there is a line coming from the brake booster and going to some black thing again on the plenum (see pic 2) now i turned that part and pulled it out and noticed a bunch of black crap on it so i put my finger inside the hole and felt around, when i pulled my finger out it was covered with black oily crud. Is that crud supose to be inside the plenum and i need names for the parts. Were someone teed in the vac line, is that ok

[viggy58]

year, make and model please....

i'm pretty sure that T shouldn't be there. the line to the brake booster and the plenum should be relatively clean. that t may be preventing the PCV system from working properly...

check engine light on?

[old_master]

I'd remove the fittings and take them to the dealer, tell them you want new ones. Yours appear to be broken and probably causing a vacuum leak; tape is not the answer! The new fittings should come with new O rings. If I remember right, the one on the PCV valve has another vacuum tee on it besides the line for the PCV valve. The additional tee might supply vacuum for the HVAC system and possibly 4X4 also. It's a smaller vacuum line, perhaps 5/32" diameter. There should be a check valve in the line, and a vacuum reservoir in the left fender, just forward of the hood hinge.

The "crud" inside the plenum is caused by a combination of two things: 1. When the EGR valve opens, it directs exhaust gas into the plenum for the engine to burn. The crusty black deposits are a by-product of combustion that is carried in with the EGR gasses...normal. 2. The PCV system sucks oil vapor and blowby gasses from the crankcase into the plenum. When the engine cools, the vapors in the plenum change back to a liquid. When the engine is running, the engine burns the EGR gasses and oil vapor. Perfectly normal for the oily "crud" to form, and should be cleaned out periodically.