Auto-Rx comes packaged in 12 fluid ounce bottles. That would be roughly 3/8th of a quart of volume. Two bottles would represent 3/4's of 1 quart. In virtually any 4 to 5 quart sump capacity motor this does not represent a gross overfilling of the oiling system. We are fully aware of the negative side of grossly overfilling a crankcase. Which can cause foaming or air entrapment in the motor oil and the resulting poor oil film. If you want to be a perfectionist, you could consider the 12 fluid ounces and add 12 fluid ounces less of the host motor oil, in order to be perfect on the dipstick line. However, there is a little wiggle room on the full mark of a dipstick. Perhaps there might be some comfort to know that beyond the cleaning esters used in Auto-Rx we also include an ester group that is designed to sturdy the oil film, that minimizes or eliminates fish eyes or the uneven spreading of the oil film on metal parts.
