There are different regulations in Europe, when compared to the United States, with regards to what may be labeled as Synthetic Motor oil. In the US group III oils, which are merely more highly refined mineral oil base oils, can be labeled synthetic oil. The further refining provides for longer life, by eliminating impurities found in a conventional oil, which ultimately means that the oil is self contaminating to some extent. Also the pour point is usually improved over what a group II performs at. So in the US, a group III oil that has shown to provide additional service life and better pour point, when compared to conventional or group II oil, can be labeled synthetic in the US. This is not the case in Europe. In the United States a couple of group III oils are labeled as Castrol Syntec and Pennsoil Platenum. These oils would be perfectly suitable for your motor applications. I dont know what the oil product labels are in Spain.
One thing to keep in mind when considering an oil choice is that you are going to be running the oil for a relatively short period of operation when compared to your normal run on full synthetic oil. We recommend a cleaning cycle with Auto-Rx installed for a total of 3000 miles or roughly 4800 kilometers. Followed by a rinse cycle of 3000 miles or 4800 kilometers, with no Auto-Rx installed for the basic cleaning application of the product. Auto-Rx works most effectively in cleaning internal engine deposits in mineral based oils, either simple conventional group II or more highly refined group III.
What may be recommended for your motors is what is known as group IV, full synthetic motor oils. These group IV use a PAO oil base. And because the PAO does not readily accept the additives that the oil company includes in oil, they use esters to couple or suspend their additive packages into the PAO base oil. The level of esters used to perform this coupling can be as high as 25%. Esters have a polar attraction to metals in general. Auto-Rx is also made of 3 different esters. Auto-Rx works most efficiently when it is the dominant ester in the oiling system. So by putting Auto-Rx into a group IV PAO oil the cleaning esters of Auto-Rx represent only 9% of the volume and the esters used by the oil manufacturer represent 20 to 25%. So the cleaning esters of Auto-Rx somewhat compete for the metal surface areas with the coupling esters that are part of the full synthetic oil. The polar esters in the PAO oil are not great for the rinse cycle either and in some respects tend to hold the deposits to the metal. So I highly recommend finding a group III oil for your motor applications.
Can a motor be cleaned with Auto-Rx in a group IV oil. Yes, however it cleans much slower, because of the competing esters. Good results can be obtained by increasing the mile in both the cleaning phase, with Auto-Rx installed, and the rinse phase with no Auto-Rx installed. We recommend running the clean cycle up to 4000 miles or roughly 6400 kilometers. Then followed by a rinse for the same mileage.
I hope this information is helpful to you. Please forward any further questions you may have.
