In this work, for a PAG (called in this work PAG0) we have estimated an average molecular weight from by mass spectroscopy using the fast atom bombardment (FAB) technique and measured the densities in a temperature range from 283.15 K to 333.15 K and at atmospheric pressure. These data were used to determine PC-SAFT parameters, which can reproduce the densities with relative deviations lower than 0.5%. Solubility data of CO2 in PAG0 and in other four PAGs(1-4) were fitted with PC-SAFT equation and the Berthelot-Lorentz combining rule using an optimized binary interaction parameter, kij showing linear dependence on temperature. Because of no densities or vapour pressure are available for PAG1 to PAG3, we have used for these lubricants the same molecular parameters as those of PAG0. Experimental data have shown immiscibility regions at mass fraction of CO2 (wCO2) >0.3. PC-SAFT equation with molecular and kij parameters determined in this work can predict these immiscibility regions (see example in figure 1). In addition, PC-SAFT predicts saturated densities of CO2+PAG5 with relative deviations lower than 6%.