renault 19 overheating after thermostat changed

Hi to all
I have a 1991 renault 19 1.4 energy that keeps on overheating, the thermostat has been changed several times and checked to make sure it is working and also the thermostastic rad/fan switch changed. The temperature just keeps creeping up and up until i get steam coming out of the bonnet - oops not good. The only way to stop it overheating is to rip the guts out of the thermostat so it is permanently open, but poor old me and little boy then have no heat in car, but this does keep the temp gauge virtually on cold. ooo and other strange thing, for some reason when thermostat has guts ripped out the fan does work in traffic when temp rises, but with a correctly working thermostat installed for some reason it blows the rad thermostatic switch, bizarre hey!!!
really hope someone might have a clue how to help, would be very much appreciated
Lisa

Hi,
I used to be a dealership renault mechanic many moons ago. It sounds to me like you are not bleeding all the air out after opening the system. There are bleed screws on the upper hose and the thing to do is to use an extention on the radiatot hill cap to raise the inlet up higher than the bleed screw. this will get all the air otu of the system.
Regards