Understanding exactly what Auto-Rx does for your engine, gets at times confusing. Every engine has
third party abrasives lodged in hard to get to oil passages, some older cars, have dirt and carbon all in the engine, and some are unlucky enough to have "Sludge" even if they are fairly new cars. Auto-Rx is a non hazardous-safe chemistry that has nothing to do with oil or oil properties.IT IS NOT AN OIL ADDITIVE. Auto-Rx has only one function which is to clean & prep your metal lubricated rotating parts to get maximum lubrication to "ALL the Metal", no matter where it is hidden; abrasives, dirt, carbon or sludge in your engine.
Synthetic Esters are not able to "clean " deep enough to be effective. Auto-Rx is "ALL' natural and actually liquifys every piece of "Crud' it comes in contact with then holds it in suspension and drive it to the filter. If you use "Dino" or "Synthetic" after prepping metal with Auto-Rx your going to get maximum performance from that oil. Solvents, ATF Fluid don't do this they seem inexpensive,in the long run they are going to very costly and they never work and surely are not safe for you, your car or our environment.