We all rant and rave about M1 and engine cleanliness. Apparently now M1 may no longer have Esters. If this is now the case is M1 any cleaner than Chevron or Pennzoil? Perhaps the prime difference is that PAO's are more sludge RESISTANT than a group IIA or so but both M1 and dino will share similar inorganic detergent and dispersant agents? (Esters being the organic one that is) There that is my million dollar question! This changeover to Ester delete now makes Amsoil, Redline, Synergyn, GC and Royal Purple more attractive in my opinion.