The viscoelastic knowledge of crude oil is limited by the complexity and variability of the raw material. Viscoelastic models of Maxwell type describe widely Mexican crude oils when an Oldroyd contravariant derivative is considered. Moreover, a Weissenberg number is defined by the product of the shear rate and the characteristic time constituted by the inverse of the rate constant of C-C bonds rotations of alkanes. This dimensionless number allows the scaling of viscosities of both crude oil, at different temperatures, and mixtures of n-eicosane/n-heptadecane. Blends of linear alkanes can simulate the viscous behavior of crude oil after adequate scaling and can be used to predict crude oil rheological properties with the advantage to be completely known and reproducible systems. (c) 2005 Elsevier Ltd. All rights reserved.