I currently have a 94 Volvo 850 that is in storage from April-December and then used as a winter car. It sees about 4000 miles a year in the winter and this winter I have decided to go two years on a fill of Rotella T6. I am wondering if since the car was in storage so long does that have any negative effects on the oil itself? I normally try and take it out for a drive about once a month to two while in storage and get it up to operating temperature on the highway to burn off any possible condensation that may have accumulated. I would like to be able to go two years on a fill but if storage has any ill effects on the oil I am not against changing it every season.