Not necessarily. It may have been their latest SM formula sold before they were licensed to label it as such.quote:
Originally posted by KJA426:
I've been using mostly Pennzoil with the occasional dose of Castrol. I noticed the last batch of Pennzoil 30 was still SL rated so I assume it has the higher levels of zinc and phosphorous.
I used to be under the impression that SAE 30 had to be (by definition) a Group I oil. However - Pennzoil labels HD-30 as using "PureBase" (Group II) and the only viscosity requirement is that it meets 30 weight at 100°C.