Thermostat Housing: Service and Repair

WM 195519 Removing and installing housing for coolant regulator

Preliminary work

1. Remove intake-air distributor -> 244619 Removing and installing intake-air distributor - section on "Removing" Overhaul.
2. Remove fuel distributor pipe -> 243019 Removing and installing fuel distributor pipe - section on "Removing" Service and Repair.
3. Remove water pump -> 195019 Removing and installing coolant pump - section on "Removing" Service and Repair.
4. Remove thermostat insert. -> 195819 Removing and installing coolant regulator (thermostat insert) - section on "Removing" 195819 Removing and installing coolant regulator (thermostat).

Removing housing for coolant regulator

1. Disconnect the front coolant hoses from the two thermostat housing pipes. => Coolant hoses to radiator (illustration as example)





Coolant hoses to radiator (illustration as example)

2. Disconnect small coolant pipe at the side -4- , pull it forward and set it aside. To do this, remove the screw -3- and pull off the pipe.





Coolant return line





3. Detach vent line at the cylinder heads. => Vent line





Vent line





Overview of ventilation





3.1. Unscrew fastening screws -1-.
3.2. Remove vent line -2-.
4. Remove screws for the wiring harness at the cylinder heads and at the water guide and loosen the wiring harness. => Wire harness for engine





Wire harness for engine

5. Remove screws for thermostat housing -2- and loosen thermostat housing -1- in an upward direction. The coolant pipe -1- (bottom illustration) remains fitted in the thermostat housing.





Thermostat housing and coolant regulator









Coolant guide





6. Remove both coolant hoses from the coolant pipe behind the cable duct (illustration shows a number of coolant hoses). => Coolant hoses Remove thermostat housing with coolant pipe.





Coolant hoses

7. Disconnect thermostat housing and coolant pipe if necessary. Replace sealing rings.

Installing housing for coolant regulator

Information

- The tightening specifications for the basic engine are stored centrally. -> 1001IN Tightening torques, tightening sequences, assembly overviews [1][2]Specifications. Tightening torques and assembly instructions for other assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.

1. The components are installed in reverse order to removal.
2. Sealing rings must be replaced.
3. Insert coolant pipe with new sealing rings into the thermostat housing following disassembly. Insert sealing rings with grease 000.043.204.68.
4. Insert thermostat housing together with coolant pipe and screw down in the tightening sequence. => Tightening sequence for thermostat housing





Tightening sequence for thermostat housing

Subsequent work

1. Fit thermostat insert (coolant regulator). For details, see -> 195819 Removing and installing coolant regulator (thermostat insert) 195819 Removing and installing coolant regulator (thermostat)
2. Fit water pump. -> 195019 Removing and installing coolant pump Service and Repair
3. Fit the fuel distributor pipe. -> 243019 Removing and installing fuel distributor pipe Service and Repair
4. Fit intake-air distributor. -> 244619 Removing and installing intake-air distributor Overhaul