Good, I have a nuance of the year 99 with enough km .. I change the oil every 5000 km approx .. and it is up soon, I usually use 15W40 Valvoline, I would like an opinion if the viscosity is correct, and if they recommend a particular mark. I am from Venezuela.
This viscity is well, Venezuela has no extreme temperatures, what you can do is put an oil for high mileage which contains special additives for engines with high mileage.
It is true 15W40 This perfect brand is just opinion thing Valvoline is not bad at all, you don't change viscosity for a thicker because they get noise.