  The ALEPH data on the (non-strange) vector and axial-vector spectral
functions, extracted from tau-lepton decays, is used in order to search for
evidence for a dimension-two contribution, $C_{2 V,A}$, to the Operator Product
Expansion (other than $d=2$ quark mass terms). This is done by means of a
dimension-two Finite Energy Sum Rule, which relates QCD to the experimental
hadronic information. The average $C_{2} \equiv (C_{2V} + C_{2A})/2$ is
remarkably stable against variations in the continuum threshold, but depends
rather strongly on $\Lambda_{QCD}$. Given the current wide spread in the values
of $\Lambda_{QCD}$, as extracted from different experiments, we would
conservatively conclude from our analysis that $C_{2}$ is consistent with zero.
