The invention concerns an absorption cooling system for a motor vehicle using water as coolant and an absorbent. Said system comprises a circuit designed to ensure circulation of the coolant, when the engine is stopped, from the evaporator (3) to the absorber (4) passing through the electromagnetic valve (10) through the continued operation of the evaporator pump (7) for a predetermined duration and through maintaining the electromagnetic valve (10) in open position after the engine has stopped for another predetermined duration before it is closed. The evaporator pump (7) is kept in operation upon closure of the electromagnetic valve (10) so as to allow the coolant to circulate in the circuit from the evaporator (3) to the boiler (1) passing through the exchanger (6). Said system enables, when the engine is stopped, the zones containing residual deposits of absorbent to be diluted thereby preventing crystallization of said residual deposits.