Thermostat: Service and Repair

Thermostat, replacing

Removing the thermostat





Remove
- the clamp holding the return hose for the power steering
- the screw holding the engine stabilizer brace to the bracket on the engine
- the screws holding the engine stabilizer brace to the suspension turrets
- the engine stabilizer brace
- the expansion tank cap.
Raise the car. Remove the lower splashguard.
Position a container under the engine drain cock. Drain the coolant.
Close the cock.
Install the lower splash guard.
Lower the car.




- the plastic hoses between the turbocharger (TC) / charge air cooler and the air cleaner (ACL) / turbocharger (TC). Applies only to B6xx4T engines.





Lift up the servo reservoir and place it on top of the engine.

Warning! Seal the cover for the servo reservoir. Check that no oil leaks out. Servo oil is highly inflammable.

Note! Ensure that the timing belt cover has cleared the nipple on the thermostat housing before the cover is pulled up.

Remove:
- the screw for the front timing belt cover. Applies only to B6xx4T Cars with chassis number 203779-
- the timing belt cover. Use a weatherstrip tool.




- the thermostat housing cover
- the thermostat.

Installing the thermostat





Note! Clean all mating surfaces. Ensure that no dirt enters the fluid ducts.

Note! Ensure that the timing belt cover is in position before the cover is pressed in against the rear timing belt cover to prevent damage to the nipple on the thermostat housing.

Install
- the new thermostat
- the cover of the thermostat housing with a new gasket. Tighten to 17 Nm
- the front timing belt cover. The mudguard over the right drive shaft boot may come loose. If this happens, secure it from underneath
- the screw for the front timing belt cover. Tighten to 12 Nm. Applies only to B6xx4T Cars with chassis number 203779-.




- the plastic hoses between the turbocharger (TC) / charge air cooler and the air cleaner (ACL) / turbocharger (TC). Applies only to B6xx4T engines.




- the servo reservoir. Check that the hoses are correctly positioned
- the engine stabilizer brace
- the screws holding the engine stabilizer brace to the suspension turrets. Tighten to 50 Nm
- the screw holding the engine stabilizer brace to the bracket on the engine. Tighten to 80 Nm
- the clamp holding the return hose for the power steering.

Carry out a function test
Fill with coolant.
Install the cap on the expansion tank.
Test drive the engine until the thermostat has opened.
Top up the coolant if necessary.