I just got my second UOA on Schaeffer 9000 on my 2004 F250 6.0L with 40,000 miles and on both reports, lead has jumped up. It went from 1-2 ppm that I was previously getting with Motorcraft 15W-40, up to 10 and 18 ppm on the two Schaeffer cycles (5200 and 4200 miles respectively). Iron is at 21 and 18, which is about where it was with the 15W-40, but the lead concerns me somewhat.
I don't think this is a case of accumulating lead, given the 20% shorter second interval vs. the 180% increase in lead. Both Schaeffer cycles did have more towing on them than usual (for me), so that may partly explain it, but I'm still puzzled why lead would increase by a factor of 10+ using high quality synthetic from where it was previously using dino. I'm also puzzled why copper and tin have not budged from 4 and 0, respectively, while lead is increasing. Surely there aren't solid lead bearings in these engines, are there? Any ideas?
I don't think this is a case of accumulating lead, given the 20% shorter second interval vs. the 180% increase in lead. Both Schaeffer cycles did have more towing on them than usual (for me), so that may partly explain it, but I'm still puzzled why lead would increase by a factor of 10+ using high quality synthetic from where it was previously using dino. I'm also puzzled why copper and tin have not budged from 4 and 0, respectively, while lead is increasing. Surely there aren't solid lead bearings in these engines, are there? Any ideas?