Thermostat: Service and Repair

Removing and installing coolant regulator (thermostat)
Tools





Preliminary work

Draining Cooling System:

1. Drain cooling system.
2. Remove intake-air distributor.

Information
Component overview

Install Location:

Component Overview:

Removing thermostat

Spring Band Clamps For Coolant Lines On Thermostat Housing:

1. Remove the two coolant lines on the thermostat housing cover. To do this, remove the spring-band clamps and pull off the hoses.

Cable Duct Over Coolant Pump:

2. Pull off the cable duct upwards over the coolant pump.
3. Release the upper fastening screw of the oil dipstick.

Fastening Screw On The Cable Duct:

4. Loosen the fastening screw on the cable duct.

Spring Band Clamp For Coolant Return To Generator:

5. Disconnect the coolant outlet on the generator. To do this, open the spring-band clamps and pull off the hose. Collect the draining coolant.

Fastening Screw For Coolant Return Line To Thermostat Housing:

6. Remove the coolant return line on the thermostat housing. To do this, loosen the fastening screw and pull off the line.

Button On The Vent Lines Of Cylinder Heads:

7. Disconnect vent line for cylinder heads. To do this, press the ribbed surfaces of the buttons and pull off the plugs.

Fastening Screws Of Heater Pipes:

8. Undo the 3 rear fastening screws of the heater pipes.

Loosening Sequence For Thermostat Housing:

9. Undo the thermostat housing cover. The sequence shown must be observed when doing so.

Removing Thermostat With Assembly Aid:

10. Lift the housing cover. Remove the thermostat using assembly aid 9627.

Installing thermostat

Note: All seals between opened sealing surfaces must be replaced.

Inserting Thermostat Into Cover And Twisting:

View Shows Assembly Using The Special Tool:

1. Insert thermostat in the cover and turn it until the two sheetmetal edges are lying to the left and right of the holder.
2. Replace inner and outer seal in thermostat housing cover.

Tightening Sequence For Thermostat Housing Fastening Screw:

3. Position thermostat housing cover and tighten the fastening screws (M6 x 25) according to the sequence shown. Tightening torque 7.5 ft. lbs..

Fastening Screws Of Heater Pipes:

4. Tighten the three rear fastening screws (M6 x 16) on the heater pipes. Tightening torque 7.5 ft. lbs..

Vent Lines For Cylinder Heads:

5. Connect vent lines for cylinder heads. The connectors must engage audibly.

Coolant Line To Generator:

6. Fit coolant line leading to the generator. Insert the line in the thermostat housing cover and tighten the fastening screw. Tightening torque 7.5 ft. lbs..

Spring Band Clamp For Coolant Line To Generator:

7. Push coolant line onto generator and fit the spring-band clamp.

Fastening Screw, Support To Timing-Case Cover:

8. Push the holder onto the timing case cover below the cable duct and tighten the fastening screw. Tightening torque 7.5 ft. lbs..

Fastening Screw For Oil Dipstick:

9. Tighten the upper fastening screw of the oil dipstick. Tightening torque 7.5 ft. lbs..

Push The Cable Duct Onto The Retaining Bracket Over The Coolant Pump:

10. Push the cable duct onto the retaining bracket over the coolant pump.
11. Check whether the drive belt is correctly installed.





12. Fit coolant supply and return hose on thermostat housing cover.

Subsequent work

1. Install intake distributor.
2. Fill coolant system and check for leaks.