take a damn look for yourself it doesn't cost you anything to spin off an oil filter....also check to see if he put to much new oil in, if its over filled it can cause more problems then just leaking oil, you can blow the motor that way....maybe he forgot to drain the old oil first...who knows Id be checking though don't start it up until you know for sure...most on here will tell you 3.7 qts of oil and some will use 4 qts but never use any more then that ever.....IM not intirely sure there is an oil pressure regulator either maybe ba busa or someone else will know that...seems to me it is mechanical and thus couldnt be regulated in anyway....