FWIW, Pennzoil is still excellent quality oil, the reason they make it from NG now is because crude oil is always contaminated by dirt, because it comes from the ground. If they use the natural gas it comes out much cleaner than oil made from crude.
From Pennzoil's website:
Pennzoil took the 100% Pennsylvania crude off of the cans back in the 70s, so you haven't been receiving 100% PA crude oil for decades in Pennzoil products.
Hot Shots Secret/LSI (Lubrications Specialties Inc.) tested new Rotella as it come from the bottle, and it has quite a bit of solids still floating in it. Here's the particle count of new oil chart. The third one is Shell Rotella brand new:
One of the reasons I use a by pass oil filter on my own vehicles, new oil just isn't as pure as you think it would be. And after you start the car it degrades from that point.
Also note that Pennzoil, and Quaker State are both now owned by SOPUS, or Shell Oil Products U.S.
Shell, Pennzoil and Quaker State, are all very similar. There are some differences and areas where the products don't overlap, such as specialty oils that one brand may cater to that not all are available under the other two labels.
In the past I was a Pennzoil dealer, that was in 1977. I have all the faith in their products as I did back then when they were headquartered in Rouseville PA. I believe that Quaker State has actually improved under the Shell umbrella.
Back in the late 70s the Pennzoil refinery workers were on strike each rail car was tested as it arrived at the refinery, before they refused, or received it. One of the salesmen that had my account was working during the strike. He told me that the railcars that were refused by Pennzoil, were then sent to Quaker State, because their requirements were no where as tight as Pennzoil's were.
One other thing I also heard, was that in the 70s Quaker State decided they knew more about additive packages than the companies that supplied most oil companies. They made their own additive package, and it ended up with a gray deposit in the engines, even if the oil as changed as per manufacturers schedule.
When I started wrenching upon graduation in 1970, I saw countless cars that had this gray deposit under the valve covers. Invariably I'd ask the owners if they were using Quaker State, and the answer was always, yes. Latter years they did go back to industry suppliers of the additive package, abandoning their home brew additives.
Living in Erie PA (only about 40 miles from Oil City PA) for 47 years, you find out some things most people never have access to.
