The oil pressure sending unit, or switch, is located on the back side of the engine. The switch informs the car's main computer, the powertrain control module (PCM), of engine oil pressure. Sometimes the switches no longer seal and leak oil. I recommend having a professional shop perform the repair. You can find a reputable facility here: https://repairpal.com/repair-shops
RepairPal Certified shops can diagnose and repair your 2005 Chrysler PT Cruiser. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.