Experimental data are reported of excess molar volumes V-E of binary and of excess molar enthalpies H-E of ternary mixtures of methanol, tert-amyl methyl ether (TAME) and n-heptane or 2,2,4-trimethylpentane (iso-octane) as well as isothermal vapor-liquid equilibrium (VLE) data of binary and ternary mixtures containing these components. The experimental data are used to test the applicability of the ERAS and the UNIQUAC model to describe the various excess properties. In particular, the possibility is tested to predict ternary data using only binary model parameters.