To clarify the effect of diesel fuel properties and engine operating conditions on engine exhaust valve sticking in the cold climate, we conducted bench engine tests on 6 sample fuels using a large size construction machine engine. From the results, it becomes clear that the ignition load limits are proportion as to the fuel cetane number and that the composition of discharged tar, generated by misfiring, agrees with a heavier part of fuel distillation region. The conditions under which discharged tar stiffens were also clarified. The intensity of valve sticking has a good correlation with 50% distillation point but does not correlate with cetane number. The heavier distillation fuel caused the valve train failure by the exhaust valve sticking.