Actually, Mobil 1 has gone to a Grp III (Same as Castrol Synetc) in some of it's applications. Mobil 1 5w-30 is actually a "thin" 30w on the viscosity charts.Piloter said:Mobil One 5-30. Tried the Castrol of the same viscosity, it burned even more quickly than the dino oils. Apparently it's not a 'true' synthetic?
Anyone that would say this doesn't know much about synthetic oil. Just because they are a mechanic doesn't mean they know what they are talking about in regard to oil.htoler said:well talked to a Toyota mechanic and he said he would not use synthetic oil in any engine unless it was designed to run it..