Might wanna POP off the Valve cover to take a look! i never had on my girlfriend 99infiniti g20 and now the motor is swaped out for a new one .. and when i look at the bad motor valve cover , it has dark oil slime look alike all over it that u can scraped it off with your finger... i had always put synthetic oil and change out every 5k.. but this is a 2nd owner car.. only put 45k on motor and the car is only 99k and only had it for 2yrs... which sux