D1146/D1146TI/DE08TIS MAINTENANCE MANUAL 1.2.3. Oil gallery cooling type piston (DE08TIS) When thermal loading is high, piston cooling by means of an oil gallery in the crown is Oil gallery cooling is used for the piston of DE08TIS diesel engine. normally necessary to prevent crown cracking and ring sticking. The design of the gallery, the design and location of the oil spray nozzle and the quantity of oil flowing in the gallery are critical in order to achieve the desired temperature reduction. The cross section shape of the gallery should be designed to achieve sufficient oil movement to maximize cooling efficiency. M1255 3 Printed in Jan. 2001 PS-MMA0415-E1A