what kind of oil

5-30 if less than 100k mile. 10-30 if over

5w30 no matter the miles. There is no difference in the viscosity between a 5w30 and a 10w30 oil when it is at operating temperature. Just buy or have a name brand 5w30 oil put in the engine along with a good quality oil filter.

5w30 if your ambient temperature drops below 30 degrees freezing and 10w30 if not

Thinking of 10w40 semi in my pt

10w40 is too heavy.

I have a 2004 PT cruiser with 105,000 miles. Would it hurt to put 10-40 mobile 1 full synthetic oil in it?