- clear access to the front of the vehicle;
- drain the coolant (see subsection 4.1). Do not open the radiator/expansion tank cap if the fluid temperature is above 90°C;
Figure 138. Method of fixing the coolant pump drive pulley from turning
- loosen the screws securing the pump drive pulley. To prevent the pulley from turning, use a screwdriver inserted between the two bolt heads as shown in the figure 138. Remove the pulley;
- remove the poly V-belt drive;
- remove the belt tensioner damper;
- remove the pulley from the crankshaft;
- unscrew the pump mounting bolts one by one and pull it out. Remove the gasket located behind it and immediately wipe the sealing surface. When reinstalling, first insert the pump mounting bolts into the holes. The pump is mounted on mounting bushings at the top and bottom;
Figure 139. Coolant pump design (2.9L engine): 1 - pump retainer; 2 — bolt, M6x12; 3 — pump drive pulley; 4 — pulley hub; 5 — bearing; 6 — bearing housing fastening bolt to pump housing; 7 - gas outlet pipe; 8 — pump body; 9 — pump body gasket; 10 — pump sealing cuff; 11 — pump impeller; 12 - pump body with internal ventilation; 13 — bolt securing the pump to the cylinder block; 14 - gasket between the pump and the cylinder block; 15 — mounting sleeve; 16 - rubber stopper; 17 — sealing ring; 18 - cork; 19 - thermostat, valve opening temperature 85°C; 20 — bolt for fastening the cover to the pump body; 21 — nipple
Information copied from the website MercedesMAN.ru
- the coolant pump can be repaired, as shown in the figure 139 parts are supplied as spare parts and can be purchased.
The pump is installed in the reverse order of removal, taking into account the following:
- if the pump body was removed, you need to put a new gasket on the drain pipe, insert it into the pump body and screw it on;
- tighten the pump mounting bolts one by one with a torque of 10 Nm;
- put on the drive pulley, screw in the bolt and, holding the pulley from turning, tighten all the bolts to a torque of 10 N·m;
- install the crankshaft pulley from the front side and the belt tensioner (see the relevant section.);
- fill with coolant, finally complete the assembly. Start the engine and, once it reaches operating temperature, check the tightness of all connections.