V-belt break
If you continue driving after a broken V-belt and therefore with the coolant pump not working, you risk serious engine damage! Although cold coolant is heavier than warm coolant, without a coolant pump, circulation is very slow and will not be enough to fully cool the engine. How to install a new V-belt, you can read in the section Generator.
Note. Recommendation: Since it is impossible to drive with a broken V-belt on the Renault 19, you should always have a spare belt in the car.