New oils with less ZDDP.

General Motors product... (E)ngine (O)il (S)upplement. You can buy it at any dealer here..I'd think there too. 1 can per oil change will do it. I run either Car Quest (valvoline) 20-50, or Castrol Syntec of various weights. In fresh engines. I'll run deisel grade oils..(fleet 15-40). Once enough miles get on it, I run full synthetic.