Thermostat: Service and Repair

NOTE: For a more accurate indication of coolant temperature, the temperature transmitter has been moved from right-hand cylinder head into the inlet connection above the coolant pump.

Previous installation position temperature transmitter (arrow):

Current installation position temperature transmitter (arrow):

Subsequent conversion on older vehicles is possible. For this purpose, install inlet connection 117 201 12 30. The existing electrical line from the temperature sensor to the coolant temperature indication in the instrument cluster can be used without change.


Removal:





1 Drain coolant. Service and Repair
2 Disconnect coolant hose from cover (14).
3 Engines 116.960 and 116.961 national versions (AUS) (J) (S) (USA) 1981 116.962, 116.963, 117.962, 117.963: Remove cover (14) and coolant thermostat.





4 Pull off single plug of electric lines on temperature switch (3) and on temperature transmitter (5).
5 Disconnect vent hose on connecting pipe (arrow).
6 Loosen hose clamp (10), unscrew fastening screws (1) and remove inlet connection (8) together with coolant thermostat.


Installation:





Engines 116.960, 116.961 standard version, 116.964, 116.965, 117.960, 117.961, 117.964,117.965, 117.967 and 117.968

7 If required, install coolant thermostat (16) with a new sealing ring (15) in such a manner that the ball valve is on the top (arrow). During installation, ensure free movement of the ball in the valve.





8 Install cover (14) and tighten fastening screws (13) to 10 Nm.





Engines 116.960 and 116.961 national versions (AUS) (J) (S) (USA) 1981
116.962, 116.963. 117.962.117.963

9 If required. fit new gasket (16) to coolant thermostat. Install coolant thermostat in inlet connection (8) in such a way that the lever (50) engages with pin (51) in the recess (arrow) and that the two ends of the spring (52) engage in the retaining lugs (dashed arrows).





10 Install inlet connection with installed coolant thermostat in such a manner that the pin (51) engages in the control bore in the cooling pump housing (dashed arrow).

Tighten fastening screws for inlet connection to 25 Nm.

11 Refit single plug of electric lines to temperature switch and temperature transmitter and connect vent hose.
12 Fill in coolant.
13 Check cooling system for leaks by pressure. testing with tester (1 bar gauge pressure).