I have deciced to switch to Mobil 1 oil . I was told the previous owner used Quaker state ..yuk.. not a fan of qs.. I have read on here that synthetics break lose the sluge. I was thinking about using an engine flush before I switch. does anyone see any problems with doing this ? Would it do any harm to the alum. engine ? Also I visted my frendily local Isuzu dealer ...Courtesy Isuzu ..in Alliance Ohio. The tech was very helpful and freindly told me to make sure i replace the" pcv valve" every other oil change if not the engine will start using oil ...and will also clog the 'EGR valve.There a smalltown dealer !!