Method and device for cooling a motor vehicle engine

The invention concerns a method for cooling a motor vehicle engine, which consists in regulating the volume and the flow rate of a coolant fluid in a hydraulic circuit ( 2 ) provided with a degassing bypass hose ( 6 ) wherein is provided a degassing box ( 11 ). The invention is characterised in that the method comprises a step which consists in determining the temperature of the cooling liquid, a step which consists in comparing the temperature of the cooling liquid with a first threshold temperature, and a step which consists in regulating the fluid circulation in the degassing bypass hose ( 6 ) such that, when the fluid temperature is higher than the first threshold, the amount of fluid circulating in the bypass hose ( 6 ) is greater than the amount circulating in that same bypass hose ( 6 ) when the fluid temperature is lower than the first threshold temperature. The invention also concerns a device for cooling a motor vehicle engine.