Multi-Grade Oils

These oils make seasonal changing unnecessary. They contain viscosity-index improvers that enable each oil to exhibit suitable flow properties at both ends of the thermometer.

They have labels like SAE 5W-30 or 10W-30 or 15W-40. Some may have labels like SAE 5W-10W-20W-30, in this case, just ignore the middle numbers and read the oil as SAE 5W-30.