Have been running UOA's for the best few oil changes on my "new-to-me" 04 Volvo S60 2.5T. The very first UOA was when i bought the car and immediately changed the oil. The next two are using Valvoline SynPower 5w-30 with Maxlife and the most recent two including the most recent are using Rotella T6 5w-40 Full syn. Wear metals are all in good shape despite my bigger turbo, injectors, and a Stage 3 tune from Hilton. However, my Sodium levels have been fairly high on all analysis' minus the very first one as they had just changed the oil before i bought it. With the absence of Potassium, I was originally thinking the sodium may have just been part of the add pack however reading up on the coolant I use in this (Zerex G-05), I found that this coolant has a high Sodium content and only around 10ppm of potassium. Does anyone think that these analysis's may actually be showing signs of a internal coolant leak instead of just add pack from the oil? Blackstone mentioned that this oil does not use Sodium in this oil however that conflicts with a few random articles i could find on the subject.