Drew99GT, I heard so much negative stuff about Pennzoil that I switched to Valvoline oil. I had been using Pennzoil but when I bought a Toyota Tercel and attended the maintenance seminar, that Toyota dealership was in the process of switching from recommending Pennzoil to recommending Valvoline. I have heard mechanics saying that Pennzoil (and Quaker State) cause sludge buildup in engines. And a couple of people who work at a Saturn dealership told me not to use Pennzoil. So did a Pike's Peak Hill Climb race car driver.
Let me tell you what I think. I do not think that Pennzoil (and Quaker State) are any different from any other conventional motor oils. In fact, based on VOAs and UOAs that people have done at this site, Pennzoil is one of the best motor oils available. Quaker State really has not been checked out too much.
As far as I know Pennzoil is still the number one brand of conventional motor oil sold in the United States. Quaker State as far as I know is number two. So what happens is, there are so many people using Pennzoil and Quaker State motor oil, mechanics are bound to see a lot of sludged up engines where people were using Pennzoil or Quaker State. When the mechanics ask the people what oil they were using, and they say Pennzoil or Quaker State, the mechanics think that they have made a connection. But if they really looked at things, they would probably realize that just as many vehicles using Valvoline or whatever are sludged up-but there are fewer people using those other brands and the mechanics do not make the connection!
They are asking people the wrong question! Instead of asking people what brand of oil they were using, when somebody brings in a sludged up engine, they need to be asking how often they changed oil. Most cases of sludge build-up are probably due to maintenance neglect, NOT TO THE BRAND OF OIL! It will maybe seem like the brand of oil, because certain brands are very popular. As long as a brand of oil makes API and SAE requirements for chemical additives and viscosity, any decent brand of motor oil should get the job done.
Of course, there have been problems recently with some cars, vans, and SUVs apparently having inherant sludge buildup problems. In these cases, it may not make a different what brand of oil you are using, you could still wind up with a problem-even if you were using Mobil 1, much less some conventional motor oil! With a lot of vehicles today, I think people would be wise to use Auto-RX (a maintenance dose) or Lube Control from the day they bought the vehicle.