I was wondering if anyone knew the levels of zinc and phosphorus in Castrol GTX 10W-40? I called and they said they could not give those numbers out?
Thanks,
Drew
Neither it nor the HM version is any higher in ZDDP than any other SN oil from what I've seen in UOA's. If you want more ZDDP you might check out Quaker State Defy or Rotella.