1999 Alero GLS 3.4, a little over 107,000 miles. I noticed tonight while waiting at Mcdonalds next to the building I could hear a ticking. I put it in neutral took it to about 1500 RPMs and it got louder. When I got home I checked the oil, and to my suprise it was full to the mark and exceptionally CLEAN. This oil change has approximently 2k on it. I am not sure what to do. I have heard of people saying to run additives to try and clear it up, and people saying not to. Thanks.