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
On a diesel engine, the thermostat in the housing is attached to the fitting on the bottom side of the coolant pump, as shown in the figure 139. Removing the thermostat is carried out as follows:
- drain the coolant as described above;
- loosen the clamp securing the cooling system hose;
- unscrew two bolts;
- remove the hose, unscrew the thermostat housing from the pump and remove it;
- remove the thermostat from the housing. In this case, pay attention to its position, which must be maintained during subsequent assembly.
Material taken from a web resource mercedesman
Assembly is carried out in reverse order. The gasket must be replaced.