EDIT: oops... this should probably be under UOA - Gasoline... I thought that's where I was. Hi, guys. I joined here after some puzzling oil analysis info that nobody seemed to be able to answer completely for me. Sooner or later, everyone referred me to this site, so here I am. I have a 2001 BMW M3 with the S54 engine. It has about 140k miles, and the bearing recall was performed at around 50k miles, so the bottom end bearings and oil pump only have about 90k miles on them. It has always been run on the recommended Castrol 10w60 specifically formulated for the S54 engine. This stuff is supposed to last 15k miles, but I have changed it every 8-10k and so have the previous owners, as shown in maintenance records. When I purchased the car, I immediately began sending in oil analysis. Unfortunately, I decided to use an octane booster for peace of mind as I was only able to get 90 octane gas during one of the fill ups at the very beginning of the first oil sample. So, lead was reading high at 39 (avg is 7 I believe). I just relaxed and filed this under the fault of the octane booster. However, my next sample still showed a higher than average lead content. This time, though, it was 32, so it is dropping, but still high. What is puzzling is that no other wear metals are even as high as the average. Iron, copper, tin, etc. are all below average or even 0... Some other facts compounding the confusion and possibilities are (I feel like I'm living an episode of "House" for mechanics): The previous owner had just performed the valve adjustment and some other maintenance, so he could have used grease, anti-seize, thread locker, assembly lube, or other things that could be in the oil... I have begun hearing a slight ticking. This is definitely not the top end. It sounds more like it is coming from the exhaust manifold and can only be heard underneath and to the passenger side (exhaust side) of the car. I am also getting intermittent check engine lights relating to O2 sensors, so I am thinking this could be an exhaust leak, cats going bad, or etc. I'm sure this is a coincidence that God has caused so that I lose sleep at night. This is what started worrying me the most, however. I have run the car in 3 SCCA autocross events so far. I am a beginner, so I was pretty slow and certainly did not even get anywhere near redline. The car redlines at 8k, and at the most I think I approached 7k for maybe half a second. Otherwise it is around 4-5k most of the time, which is a total of about 60 seconds per run. One of these events, however, is important... I forgot to check the oil before hand and was only able to check it at the track. I also only had about 1/4 of a bottle with me. When I checked it, the oil was at the low mark on the dip stick, and the extra little bit brought it just slightly above the low mark. I feel stupid about this, but I don't think that could have hurt anything. It was still within the safe region. Also, the high lead readings started before this occurrence. So, that's a long story and I still don't feel like I have included everything. Anybody have any suggestions? What could be another source of lead and no other wear metals? Could the octane booster be lingering this long? I want to believe it is something this simple, but the new noises are troubling. I have not been able to get an actual oil pressure gauge on it yet... it just has a warning light (that has never come on).