Has been overheating, not on the highway but in city driving?

My question for you is about having to add coolant all the time. My first thought about this specific concern is if coolant is not leaking onto the ground it is leaking some where. Have you checked the engine oil or if this Pt Cruiser has an automatic transmission check the transmission fluid also does the fluid appear to look like engine oil and automatic transmission fluid or does it look more like a milk shake in color? If both appear to look normal then I would have the cooling system tested for a head gasket leak. A cylinder head gasket that is leaking would allow coolant to enter the combustion chamber and would burn the coolant which would explain why your having to add coolant with no visible external coolant leak. Let me know if this answers your question or if you have any more questions.

This sounds like a blown head gasket. The engine is basically and air pump it pumps in air and compresses the air/fuel mixture. This compressed charge is ignited and the resulting explosion forces gases into the cooling system increasing the cooling system pressure (this cooling system usually runs around 16 pound of pressure. The combustion gases exceed the cooling system pressure regulator contained within the cap forcing coolant out the overflow hose. Have the cooling system tested for combustion gases. Www. Blockchek. Com describes the tool I've used to identify this type of engine failure.

Looking up the specification for this particular vehicle it should run a 16lbs pressure cap. Is the 1 missing from the six? Six is a really low pressure and I haven't see a cooling system that uses that low of pressure. As the engine is warming up the pressure in the cooling system continues to increase so a low pressure cap could cause the cooling system to depressurize premature allowing the coolant to boil and over flow. The cooling system must be pressurized in order to raise the boiling point of the coolant (like a pressure cooker in the kitchen) to operating temperature for the engine to be efficient.

A nation wide auto part supplier often rents out tools for a fee that often get reimburse in full after returning. If you can ask for a cooling system pressure tester it will apply specific pressure to the cooling system and pressure cap. This tool is used to identify leaks, so if the cap will not hold enough pressure, then it is bad.

Absolutely, have a good evening.