While 15W-40 is a common and perfectly acceptable oil for many vehicles, particularly those that work hard or operate in extreme temperatures, it's too thick for some engines. Using an oil that's too thick can hinder engine performance and even cause damage. The PT Cruiser's engine likely calls for a lighter weight oil, like 5W-20 or 5W-30.
Always consult your owner's manual. This is the only definitive source for the correct oil specifications for your specific PT Cruiser model and year. Using the wrong oil can void your warranty and damage your engine.
