Well - I just changed the oil in my 2004 WRX last night with Mobil 1 5W-30 (API SL donut and "New Car Formula" label on the front). Just over 3700 miles on the oil and 16K+ miles on the odo. Probably could have gone longer, but I felt like doing it. My last analysis from Blackstone (~3600 miles on oil) showed a relatively high copper level (24 PPM) which was attributed to slow break-in of bronze parts. Iron was at 6 PPM. I'm not sure that it was bronze, since there was no tin; might have been brass or copper. I'll probably get a UOA on the next change and increase my OCI if the copper level goes down.
I do daily stop & go driving, but get most of my miles on longer trips. Of course temperature extremes are rarely an issue here, although I did take my ride up to Tahoe when it snowed.
I do daily stop & go driving, but get most of my miles on longer trips. Of course temperature extremes are rarely an issue here, although I did take my ride up to Tahoe when it snowed.
