2002 Buick Park Avenue use of Penzoil High Mileage 5W-30 mo

some high mileage oils lack one ingredient, detergent, this can be helpful for some engines, ask them what's so special about the penzoil, if they can answer it intelligently, then maybe, but I would actually use an oil like Mobil 1 synthetic, in any engine, high mileage or new! Synthetic does a better job of carrying the dirt to the oil filter than regular oils...I use Mobil 1 in my own car.