This time at 6K miles (53k on truck) the wear metals are down some, with the iron finally getting below 20ppm. HOWEVER, the analysis last time reported about 50ppm of sodium which I attributed to winter salt. This time they have switched that analysis to 50+ppm of Potassium. I got a msd sheet for Dexcool and it shows potassium 2-ethylhexanoate as a component so I suppose I am getting some seepage at the intake manifold (no glycol detected). I wonder how long or how high I should let the K get before acting? I may post the analysis if I can dig up my last report and add on to it.