In this study the effect of varying the behavior of 457-LA diesel engine cooling system has been conducted
using research facilities installed on a test bed with W400 eddy current dynamometer. Insufficient information
on the engine thermal regime has resulted in the wrong belief that the engine performance and life can
be extended by reducing the temperature of the circulating cooling water. Theoretical studies and the experimental
results of the present study show that for an engine under loading condition, any variation in the
cooling system, particularly, reducing the cooling water temperature, increases the mechanical stresses due to
change in allowable tolerances. Other consequences, such as increased fuel consumption and pollution, result
in after burning and thermal stresses and corrosion in the exhaust system. At the same time, meaningful reduction
in measured power and torque has been observed for the case of reduced cooling water temperature.
In contrast, increase in the cooling water temperature limit, using standard and optimized diesel fuel, can
result in superior characteristics for power, torque, fuel consumption and pollution.