Oil on valve cover/under car
 

i noticed that a little bit of oil was ontop of my valve cover, and it seems to be comming from the oil cap... so my first thought was that if i replace the oil cap, the problem will go away. while inspecting the bottom of the car i noticed a drip of oil on the oil filter, and the tubes to the oil cooler were covered with oil. what could be causing this problem? i noticed it right after i got my engine back from having it rebuilt, but if it's nothing major, im not going to bother taking it somewhere, i'd rather fix it myself. thanks guys

Not actually seeing the car and what you describe I would say worst case senierio too much crankcase pressure (bad ring job,bad PCV,etc.),or loose bolts where it seals(valve covers,oil pan etc.),or excessive oil pressure.

Maybe someone missed when putting oil in it. :)

Run a compression test and see what you have. Best thing of course is to run a leakdown test and see where it is going to but a compression test will be a start.