Vern,
Just about everybody's old oil sludged up engines.
QS, Valvoline, WH,and on and on. I wouldn't condemn Castrol for that.....
Originally Posted By: Vern_in_IL
Quote:
The fuel economy attributes of Biosynthetic Base Oil are demonstrated by the results of a recent Mercedes Benz M111 Fuel Economy Test in which a Biosynthetic SAE 5W-30 motor oil formulation achieved a 3.05% fuel economy gain compared to the industry reference oil.
They should go 75% plant based, never a fan of Castrol(yesterdays oil that sludge's up motors) However I might try this because I'm a hypermiler.