Internal combustion engine cooling

An internal combustion engine cooling assembly 20 comprises a primary and secondary flow of coolant. The secondary flow of coolant is injected e.g as a jet into the primary flow of coolant in dependence upon a variable provided by a sensor 32A, 32D such as a temperature sensor, which provides an indication of the temperature of the engine body in the region 24 where the secondary flow of coolant mixes with the primary flow of coolant. The secondary flow of coolant may be a pulsed flow having a frequency 0.2 to 50 Hz. The invention provides controlled cooling at different and variable levels in one or more localised regions of the engine body such as cylinder heads. The injected jet is believed to create turbulence in the coolant flow which enhances heat transfer between the coolant and the engine. The invention leads to reduced fuel consumption and reduces engine emissions. There is also disclosed a method of cooling an internal combustion engine. In a further embodiment the invention comprises an internal combustion engine which includes passageways in the engine body 20.