Am I right to believe that there is a pressure build up inside the engine? (refer to the pictures) If so, what is causing it? Could it be the EGR valve? or PCV valve? But there is no funny noise coming from it, nor constant black smoke coming out of the tail pipe. Although, when I accelerate hard it does. One thing to note of, I am not losing engine oil and engine is not overheating. Thus, I would really not consider a major oil leak. I would say oil is seeping out of that cap on top of the engine (not really sure what it is called) through the breather hose and also much worse down the sump oil. Also, this happens only on one side of the engine (side where the cap is). On the other side is clean. I am looking at changing the oil filter, although I just had it serviced 5 months ago. Is there anything I am missing or something I need to do just to make sure that pressure is not building up inside the engine.