i bought some ramps and changed my derelict friends oil in his 98 cavalier and i could not get to the oil filter so i just drained the oil and put in synthetic...i imagine oil had at least 15k on it along with filter...a el cheapo partsmaster...his drain plug gasket was shot too but luckily for him i had a spare drain plug that come off my sunfire in mint condition...i drained the oil before i tried to change filter so i had no choice but to dump it in...he is better off now then he was before at least...maybe in 5k i will go to Walmart and have them do a OC...i might take it to a mechanic friend and see if he can do it easy...the used oil wasnt sludgy or chunky and the syn should help clean engine so this wasnt a total waste