This invention relates to a method of cooling an engine for an automobile, in particular to a method of operating a cooling system having a variable coolant flow control valve. The cooling system is operated in dependence upon the difference between a desired operating temperature and a measured operating temperature. If this difference falls within a first and a second predetermined threshold, the temperature control is effected by operation of the valve in dependence upon the difference. The method also includes operation of a variable speed fan and a variable speed pump, in dependence upon the difference between a desired operating temperature and a measured operating temperature.