That's the beauty of the whole deal....It was maintained regularly but there was no specific oil brand or type used, as being it conventional or blend oil. Overall though, the oil was changed every 5,000 miles. Oil that was used the most was TropArctic, then an occasional Pennzoil and Quaker State. The one thing (which goes against everyone who says if you go with synthetic, blend, or conventional) but the oil was changed between conventional and synthetic blend constantly. The filter's used the most was Fram for awhile until their quality became horrible, then we switched to Wix or Baldwin Filters. The vehicle was driven in a normal mode, meaning it wasn't babied and it was floored all the time. So it goes to prove all the people's dedication to using the same brand and type has been completely compromised. It just goes to prove that as long as you maintain your vehicle regularly and drive it in a good manner.