I had my oil changed Wed afternoon and put synthetic in for the first time. I got up this morning and noticed a spot of oil under the truck. After crawling under the truck and checking the plug (it was some loose) I noticed that there was a black rubber looking washer that had been torn. It is still leaking slowly even after I tightened the plug. My question is what kind of seal was on the plug originally? I have changed the oil myself most times but I don't remember it being a black rubber seal. The truck is a 2001 with 60,000 on it. Should I just order a new heavy duty plug from Geno's or can I get a new seal at a local parts store? What size is the seal and what kind is it? tia.