2013 TSB Fuel in oil.. which oil to use
 

My 2013 Mazda3i with 4 Cylinders 2.0L FI DOHC still has indications of the Mazda Technical Service Bulletin No: 01-005/15, Last Issued: 06/19/2015, Subject: CHECK ENGINE LIGHT ON.. WITH INCREASED ENGINE OIL LEVEL. I bought this CPO Mazda with just 25K miles from the dealer with no mention of any DTC being cleared but the 6+ quarts of "crankcase fluid" [dare I call it "oil"] looked like it had never been changed. So much for a 140 point Mazda CPO inspection. The TSB recommends a PCM reprogramming = $100 = Not Part of the CPO warranty. I did the full oil & filter change after the PCM update with only 4 quarts instead of 4.5 quarts. Nothing but warm weather since and the dipstick has still climbed from 1/2 to FULL. Apparently, PCM reprogramming is insufficient to overcome the poor job of Mazda valve timing & fuel injection engineering. Now I need to consider the outcome. Do I use the 0-20w grade oil Mazda specifies in the interest of fuel economy or do I use a higher viscosity to offset the thinning action of fuel in the crankcase. Mobil lubricants told me to consult Mazda and did not indicate which Mobil product best accommodates fuel contamination. I am fed up with Mazda customer service and Mazda dealers. What would your recommendation be when the crankcase is diluted with fuel? Do you increase the oil viscosity? Warmer weather persists. When the fuel evaporation from the crankcase through the EGR diminishes during colder weather, then some consideration of oil viscosity will need to be made.

I said crankcase ventilation throught the EGR when it is acutally through the PCV. Maybe I should leave the oil filler cap open a crack.