The engines in these cars are "rock solid" if the routine maintenance has been done consistently throughout the years along with normal wear & tear. To comply with factory recommendations, either one of the grades would be applicable, my opinion. With the mileage you're stating on your car, I would probably lean towards the 5w40 version - that's just me talking out loud. Both oils would provide the same level of protection & lubrication at normal engine operating temperatures. The 5w40 version would give your some added protection (increased viscosity & potential lubricity) at start-up & engine warm-up period considering the mileage on the engine which could have increased tolerances ever so slightly over the years.