A crankshaft (1) includes a first to a sixth crank pin (41 46), a first to a fourth main journal (21 24) and a first to a ninth crank arm (61 69). At least the first, the second, the eighth and the ninth crank arms (61, 62, 68, 69) have respective integral counterweights (61', 62', 68', 69') for balancing the crankshaft (1). In order to reduce bending stress on the areas where the second and the eighth crank arms (62, 68) are connected to the respective pairs of adjacent crank pins (41 42, 45 46), the axial dimensions of the first and the ninth crank arms (61, 69) are reduced, being substantially the same as those of the adjacent crank arms (62, 68) in order that the axial length of the two end spans of the crankshaft is the same as that of the intermediate span. In order to balance the crankshaft (1), two additional counterweights (71, 72) are arranged outwardly of the end journals (21, 24) and their axial dimensions are comparable to those of the end crank arms (61, 69).
A motor vehicle comprises a pre-assembled front module (1) including a support structure (2); a propulsion unit (14); a steerable front wheel assembly (17); an intermediate support structure (20) for housing and supporting a windscreen; a planar load-bearing floor structure (30); a pre-assembled intermediate module (40) including a firewall (41), instrument panel (42), steering column (43, 44) and a control pedal assembly (45); a rear pre-assembled module (50) including a support frame (51), at least one pair of rear wheels (55); an annular rear structure (60); and two side structures (70).
Circulation system for the coolant in an oil cooler (13) adapted to cool down the oil of the automatic transmission (2) of a motor vehicle in which the drain conduit (15) for the coolant from the oil cooler (13) of the transmission (2) is connected to said return conduit from the radiator, and that the exit mouth (16), of said drain conduit is inserted in the return conduit forming an angle A, said angle being more than 0.degree. and less than 90.degree..