Figure 71. Location of oil spray nozzles of the piston cooling system
Below are some of the changes made to the 601 and 602 engine family design in case you are considering replacing some parts from a similarly designated engine type. Although the engines have the same designation, this does not mean that they are absolutely the same. Since 1985, the diameter of the crankshaft bearing mounting holes has been reduced by 2 mm. The diameter of the crankshaft bearing cap mounting bolts has been reduced from M12 to M11. The bolts have double hexagon heads. Since these are flexible bolts, their length should not exceed 63.8 mm if you intend to reuse them. The mating surface of the cylinder block that contacts the cylinder head has also been modified, so such blocks must be used with correspondingly modified heads. The drain plug for the cooling system now has an M18 thread instead of the M14 thread previously. The oil supply points to the spray nozzles of the piston cooling system are located on the new engines on the right side under the cylinder liners. Figure 71 shows the location of these oil spray nozzles. If you are going to install a cylinder block from an old engine on your car, it must be equipped with oil spray nozzles for cooling the pistons. If you have any doubts about anything, please contact a Mercedes-Benz service station, as it has all the necessary technical documentation.