At finite temperatures it is known that quark-induced interaction lead
to formation of instanton-anti-instanton molecules, strongly polarize
d in time direction. We report first direct simulations of the statist
ical mechanics of the interacting instanton ensemble at finite tempera
tures. First of all, they confirmed that molecule formation is driving
the chiral phase transition. It happens at T similar or equal to 140
MeV (for two flavors) and is second order, while being weak first orde
r if quark masses are as in QCD. We also calculated the behavior of th
ermodynamics, mesonic susceptibilities and screening masses near the p
hase transition: inside uncertainties, all agrees with lattice results
. Furthermore, the first order phase transition lines extend further i
n theories with larger number of flavors N-f for sufficiently small ma
sses we have found that chiral restoration happens-at T = 0 already at
N-f = 5.