I bought a car and I will be doing an oil change and tune up this weekend. I do not know if it has synthetic in it or not. I called the napa guy and asked him what I should do and he said if I drain all the oil and then put synthetic in it it wouldnt hurt my engine but if I did it the other way around it would. I am planning to get as much of the old oil out as I can by running an extra court through to clean it out before I put the new oil in. I dont want to flush the engine with an oil flushing thing cause that may cause my engine to leak in other places. Is what the napa guy said correct? If there isnt synthetic in it and I put synthetic in will it hurt my engine?
-Xionide
-Xionide