I recently finished my Arx trtment, both "clean" and "rinse" phases. After the end of "rinse" the oil was changed to GC, and that's what I'm planning to do my uoa on.(after only 3k miles, 'cause this is my 1st time with syn/GC). I was wondering: as this is the 1st "fresh" oil immediately after Arx, could there be residue from Arx and/or other contaminents resulting from Arx which can still be in the engine and can effect values of my UOA? (I didn't do any other "flushes" after the Arx-rinse, before changing to GC). I don't want to waste my money if this could be the case. I should also mention that what I want mostly from my uoa is to see if the car has an internal coolant leak:(coolant level has been dropping a tiny bit in the reservoir tank over the winter months) is it better to wait until the next oil change, and THEN do the uoa with THAT oil? would appreciate any comments/suggestions. Thanks.