With later model crimpers you may use the following for doing reduced crimping (S = Standard R = Reduced)
S # 6 can do R # 8
S # 10 can do R # 12
For the other sizes you need specific dyes
Changing the oil in your vacuum pump is a very important step to achieving a good vacuum in the air-conditioning system. If the oil is dirty the vacuum pump will not perform and the dirty oil may damage the internals. It is recommended the oil be changed after every vacuum but this may not be appropriate for everyone’s situation so keep an eye on the oil and if it looks milky or discoloured be sure to change it! Vacuum pump oil is generally a clear golden colour.
You only need 7.5ml of dye for every 300ml of oil. In any automotive system you will only ever need to add 7.5ml of dye to the system. Dye can break down the viscosity of the oil so do not keep adding dye to a system that has had dye already introduced, even after a degas as the internal walls of the system are coated in oil and dye that have already mixed together.
A system cannot be run on nitrogen as the system will be pressurised and this WILL cause damage to the internals of the compressor.
Brand new Denso and Sanden compressors come with a factory charge of oil. For other compressor models be sure to read the information provided with the product or drain the oil to be sure.