Re: ZDDP... another oil thread
Older engines with flat tappet cams are affected by lower concentrations of ZDDP. The ZDDP levels were lowered in 2011 so what about the failures in pre- 2011 cars? Starting in 2008 subaru started using silver in their bearings and treated the crankshafts differently. Guess what ZDDP actually reacts and eats at silver so If anything higher concentrations of ZDDP would be more harmful for the bearings based on that information.
The ultimate cause for EJ257 Bearing Failure= Improper clearances from factory, debris contamination from factory, loss of oil viscosity under prolonged high rpm conditions, or damage from prolonged detonation.