Penzoil regular "conventional" oil (not synthetic) is the only oil I will ever use. Unless it's a brand spanking new car with super low miles, I would never use synthetic oil.

On engines with a decent amount of miles, the varnish build-up deposits of conventional oil actually helps "seal" the engine between the seams of various components and helps prevent oil leakage. Sometimes switching from "conventional" to "synthetic" can cause more harm than good as it removes the varnish build-up deposits that help seal the engine, thereby causing oil leaks.

Just ask VX member "HYPERKID" who switched from conventional to synthetic in his VX and it caused major oil leaks. His VX eventually leaked oil out of various engine seams at an excellerated rate and his engine fried due to lack of oil. He had to replace his VX engine for $$$. Before he switched, his VX ran fine on normal conventional oil with never a problem or leak. Lesson learned.

Plus, conventional oil is way more inexpensive than synthetic!!!