  We consider a class of heterotic N=2 -> 0 super no-scale Z_2-orbifold models.
An appropriate stringy Scherk-Schwarz supersymmetry breaking induces tree level
masses to all massless bosons of the twisted hypermultiplets and therefore
stabilizes all twisted moduli. At high supersymmetry breaking scale, the
tachyons that occur in the N=4 -> 0 parent theories are projected out, and no
Hagedorn-like instability takes place in the N=2 -> 0 models (for small enough
marginal deformations). At low supersymmetry breaking scale, the stability of
the untwisted moduli is studied at the quantum level by taking into account
both untwisted and twisted contributions to the 1-loop effective potential. The
latter depends on the specific branch of the gauge theory along which the
background can be deformed. We derive its expression in terms of all classical
marginal deformations in the pure Coulomb phase, and in some mixed
Coulomb/Higgs phases. In this class of models, the super no-scale condition
requires having at the massless level equal numbers of untwisted bosonic and
twisted fermionic degrees of freedom. Finally, we show that N=1 -> 0 super
no-scale models are obtained by implementing a second Z_2 orbifold twist on N=2
-> 0 super no-scale Z_2-orbifold models.
