Thanks all
i have done the engine flush
now the heater works fine
the engine temperature now is acceptable
80C° during normal condition
85° durning load
87C° when AC on
auxilary fan works great
engine fan is always turning with engine

i also tested the new and the old thermostat with hot water
begin to open at 71° and fully opned at 90C°
so i dont have to buy another one

oil pressure now 1.5bar i know its better than 1 bar
but before this problem happen to me oil pressure was 2 bar
i think should live with this 1.5 bar until i fit OM602 Turbo oil cooler and filter housing