I know with SOHC cams you can change it with out taking your engine out, but I pretty sure that with DOHC you have to take the engine out. But I can't garentee it. So if I were you I would search it. And if I were you I would change both of them just because it's bad to have one good gasket and one old gasket. And my car has been having problems down low in the rpm range I think I blew a headgasket and mine doesn't overheat either.