Dear customer, you can continue using the same oil that you have been using.
Let me explain what the oil nomenclature means:
Based on the acronym 5W-30, this oil would be grade 5 at low temperature and 30 at high temperature, which means that it has low viscosity properties and the engine could start at very low temperatures.
Normally after a certain time the oil with low numbering or nomenclature tend to evaporate with the passage of the route, in reality this is a test trial and error, if you felt that the oil has evaporate you must proceed to replace it to a 5W40, Then if it keeps seizing you proceed to replace it yet 10w-40 But considering your case if the last oil never goes by you can be calm and use it.
It will last 6-8 months or 5000 miles in average.
Have you understood me dear customer?
Dear Customer, my goal is to give you the best advice I can and I hope that I've helped today.
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Best regards, Sebastian.