Air conditioning Kätemittelkunde

Hello now to the X-tem times a question about the climate. It is clear that my climate was filled with the refrigerant R12 ex works. Over time, the refrigerant is disintegrating through the hoses and seals from the system and must be replenished. Since a refill with R12 has been banned in Germany in the meantime, it is necessary to avoid another remedy. All right, all right. I know two of them as exchanges. 1. r134a us 2. r413a. The conversion to r134a only goes without filling up the missing quantity, so exchange the whole quantity for r134a. This leads to problems with the existing seals in the system. Two. is there r413a which probably does not have a compatibility problem with the seals and can be taken unproblematic as a filling agent.Now I only lack the technical background with the additional oil in the plant. It serves to lubricate the compessor and how it interacts with the various cooling liquids and their mixing ratios. What is the special quality of Hella's oil, which is mentioned here in the Forum? Must change the throttle when changing. So, who knows exactly?