Bought used car, 2004 Altima, what to do.

[Mike]

The dealer I work at now avoids cars with that 2.5S engine because of various engine mechanical problems we’ve seen on it. I’d advise frequent oil and coolant changes to minimize the likelihood of having issues. Some engines are going to have problems no matter what, but if it is preventable, quality oil and coolant maintenance is what prevents them. Many headgasket problems on a variety of engines, for example, are the result of coolant deterioration allowing corrosion to occur and compromise the seal somewhere. I myself run synthetic oil in every personal/family/friends car I’m responsible for a plethora of reasons.