Cooling System: Service and Repair
Removing and installing unit carrier (coolant distributor housing)
Information
Overview of coolant distributor housing
1 - Unit carrier (coolant distributor housing)
2 - Coolant flange
3 - Bracket for coolant pump
4 - External Torx screw, M8 x 35
5 - External Torx screw, M8 x 50
6 - External Torx screw, M8 x 70
7 - Seals
8 - O-rings
Preliminary work
Danger
Vehicle can fall down
^ Risk of squashing or crushing
^ Risk of damage to the vehicle
-> Do not place any solid objects under the raised vehicle.
-> Ensure that the lifting platform is prevented from lowering.
-> Remove solid objects before lowering the vehicle.
-> Raise the vehicle only at the take-up points provided.
1. Raise the vehicle.
2. Place protective covers on the vehicle to avoid damaging the body and passenger compartment.
3. Remove underbody panels at the rear and left.
4. Remove air cleaner housing.
5. Remove resonance tube.
Securing resonance tube
6. Slacken the drive belt -1-.
Relieving drive belt
6.1. Turn the tensioner -3- clockwise at the hexagon (a/f 30) using a ring wrench -2- and remove the belt -1-.
6.2. Allow the tensioner to slide back to its initial position.
7. Detach air conditioning compressor.
8. Remove hydraulic pump.
9. Remove the generator.
Generator
9.1. Loosen external Torx screws (E12, M8) -1, 2- by two to three turns and fit screw insert (E12) with short extension on the screw head. Loosen threaded sleeves in the unit carrier by tapping gently with a plastic hammer.
9.2. Unscrew external Torx screw (E12, M8) -2- and swivel the generator up.
10. Drain coolant.
11. Remove number plate and retainer plate.
12. Remove front silencer.
13. Remove engine carrier.
Removing unit carrier (coolant distributor housing)
1. Remove engine carrier bracket.
1.1. Loosen and unscrew M10 threaded bolts.
Threaded bolts
1.1.1. Screw two M10 nuts -1- onto the M10 threaded bolts -2- to lock them.
1.1.2. Unscrew M10 threaded bolts -2-.
1.2. Remove the engine carrier bracket -3-.
1.3. Clean the threaded bolts and thread in the crankcase (adhesive residue) and remove any traces of grease (using brake cleaner) by blowing out the threaded bore with compressed air.
2. Remove the drive belt -1-.
Drive belt
3. Remove the vibration damper -1-.
Disconnecting vibration damper
4. Remove water connection piece.
Water connection piece
4.1. Loosen the vacuum line at the water connection piece -3-.
Unscrew one external Torx screw (E10, M6 x 12) -2- on the water connection piece -3-.
4.2. Remove water connection piece -3-.
Unscrew three external Torx screws (E10, M6 x 25) -1- on the bracket for the coolant pump -5- and crankcase and remove the water connection piece -3-.
Intake tube and thermostat housing
5. Remove thermostat housing lid.
The thermostat housing is in two parts, which can only be removed separately. Removing the unit carrier simply involves removing the intake tube -1- to the thermostat housing and loosening the thermostat housing underneath.
5.1. Remove coolant hose on the thermostat housing lid -1- by releasing and pulling off the spring band clamp.
5.2. Loosen one external Torx screw (E10, M6 x 40) -2- by two to three turns.
5.3. Loosen and unscrew two external Torx screws (E10, M6 x 12) -4- on the intake coolant pipe -5- at the thermostat housing and high-pressure pump holder.
5.4. Pull intake coolant pipe -5- out of the thermostat housing.
5.5. Loosen and unscrew three external Torx screws (E10, M6 x 50) -3- on the thermostat housing lid -1- and remove the thermostat housing lid -1-.
5.6. Loosen and unscrew one external Torx screw (E10, M6 x 50) at the bottom of the thermostat housing.
6. Remove bracket for the coolant pump.
Bracket for coolant pump
1 - Bracket for coolant pump
3 - External Torx screw, M8 x 50
4 - External Torx screw, M8 x 50
5 - External Torx screw, M6 x 20
6 - External Torx screw, M8 x 25
7 - M10 threaded bolt (already removed)
To remove the external Torx screw -4-, the tensioner must be turned and locked.
6.1. Loosen and unscrew external Torx screws -3, 4, 5, 6-.
Removing bracket for coolant pump
6.2. Remove bracket for coolant pump.
6.2.1. Turn bracket for the coolant pump -1- slightly until the bars on the bracket for the coolant pump -1- and thermostat housing -7- are exposed -arrow-.
6.2.2. Pull bracket for coolant pump -1- off to the rear.
7. Remove unit carrier (coolant distributor housing)
7.1. Remove coolant connection piece.
Unit carrier (coolant distributor housing)
1 - External Torx screws, M8 x 70
3 - Coolant connection piece
4 - External Torx screw, M8 x 50
5 - External Torx screw, M8 x 50
6 - Unit carrier
7 - Thermostat housing
7.1.1. Release spring clamps at the Henn couplings and pull off coolant hose at the coolant connecting piece -3-. Make sure that the spring clamps are not overstretched.
7.1.2. Release and pull off spring band clamp on coolant hose.
7.1.3. Loosen and unscrew three external Torx screws (E12, M8 x 70) -1- and remove the coolant connection piece -3-.
7.2. Disconnect cable plug on the coolant temperature sensor.
7.3. Unscrew three external Torx screws (E12, M8 x 50) -4, 5-.
7.4. Carefully pull the unit carrier -6- off the thermostat housing -7- and remove it.
Installing unit carrier (coolant distributor housing)
1. Replace two seals and two O-rings on the unit carrier. Replace one seal on the coolant connection piece.
Seals on unit carrier
2. Replace moulded seal on the connecting tube -3-.
Thermostat housing and connecting tube for coolant pump
3. Install unit carrier (coolant distributor housing).
Unit carrier (coolant distributor housing)
1 - External Torx screws, M8 x 70
3 - Coolant connection piece
4 - External Torx screw, M8 x 50
5 - External Torx screw, M8 x 50
6 - Unit carrier
7 - Thermostat housing
3.1. Insert unit carrier -6- into the thermostat housing -7-.
3.2. Screw in and tighten three external Torx screws (E12, M8 x 50) -4, 5- on the unit carrier.
-> Tightening torque: 33 Nm (24 ft lb.)
3.3. Connect cable plug on the coolant temperature sensor.
3.4. Install coolant connection piece.
3.4.1. Fit coolant connection piece -3- and tighten M8 x 70 Torx screws -1-.
-> Tightening torque: 33 Nm (24 ft lb.)
3.4.2. Fit and secure spring band clamp on coolant hose.
3.4.3. Fit coolant hose on coolant connection piece -3- and secure with spring clamps on the Henn couplings. Make sure that the Henn coupling locks with an audible click.
4. Install bracket for the coolant pump.
4.1. Replace O-rings.
Grease new O-rings with Kluberplus Gel (Part No. 000.043.205.93).
4.2. Fit bracket for coolant pump -1-.
Coolant connection piece
4.2.1. Turn bracket for coolant pump -1- slightly and guide into position from the right.
4.2.2. Carefully press bracket for coolant pump into the mounting -1-.
4.3. Secure bracket for coolant pump -1-.
Bracket for coolant pump
1 - Bracket for coolant pump
3 - External Torx screw, M8 x 50
4 - External Torx screw, M8 x 50
5 - External Torx screw, M6 x 20
6 - External Torx screw, M8 x 25
4.3.1. Screw in and tighten external Torx screws -3, 4, 5 and 6-.
4.3.2. Tighten one external Torx screw (E10, M6 x 20) -5-.
-> Tightening torque: 13 Nm (9.5 ft lb.)
4.3.3. Fit and tighten one external Torx screw (E12, M8 x 25) -6-.
-> Tightening torque: 33 Nm (24 ft lb.)
4.3.4. Tighten two external Torx screws (E12, M8 x 50) -3- and -4-.
To tighten the external Torx screw -4-, the tensioner must be turned and locked.
-> Tightening torque: 33 Nm (24 ft lb.)
5. Install thermostat housing lid.
Intake tube and thermostat housing
5.1. Secure thermostat housing lid -1-.
5.1.1. Fit and tighten one external Torx screw (E10, M6 x 50) at the bottom of the thermostat housing.
-> Tightening torque: 13 Nm (9.5 ft lb.)
5.1.2. Fit thermostat housing lid -1- and screw in and tighten three external Torx screws (E10, M6 x 50) -3-.
-> Tightening torque: 13 Nm (9.5 ft lb.)
5.1.3. Tighten one external Torx screw (E10, M6 x 40) -2-.
-> Tightening torque: 13 Nm (9.5 ft lb.)
5.2. Secure intake coolant pipe -5-.
5.2.1. Replace O-rings.
Grease new O-rings with Kluberplus Gel (Part No. 000.043.205.93).
5.2.2. Press intake coolant pipe -5- into the thermostat housing.
5.2.3. Fit and tighten two external Torx screws (E10, M6 x 12) -4- on the intake coolant pipe -5-.
-> Tightening torque: 13 Nm (9.5 ft lb.)
5.3. Connect coolant hose to the thermostat housing lid -1- and secure with a spring band clamp.
6. Install water connection piece -3-.
Water connection piece
6.1. Fit water connection piece -3-.
6.2. Screw in and tighten six external Torx screws (E10, M6 x 25) -1- on the bracket for the coolant pump -5- and crankcase.
-> Tightening torque: 13 Nm (9.5 ft lb.)
6.3. Secure the vacuum line at the water connection piece -3-.
Screw in and tighten one external Torx screw (E10, M6 x 12) -2-.
-> Tightening torque: 13 Nm (9.5 ft lb.)
7. Install vibration damper -1-.
Installing vibration damper
Information
The threaded bolt on the bracket for the engine carrier must be bonded using Loctite 243 and can only be subjected to pressure after a hardening time of three hours.
8. Install engine carrier bracket.
8.1. Fit the drive belt -1- on the vibration damper.
Drive belt
8.2. Fit the engine carrier bracket -3-.
8.3. Apply Loctite to the threaded bolt (stud) M10 x 120.
8.4. Screw in and tighten threaded bolt (stud) M10 x 120.
Threaded bolt (stud)
Screw two nuts -1- onto the M10 x 120 threaded bolt -2- to lock it and tighten the threaded bolt -2-.
-> Tightening torque: 5 Nm (3.5 ft lb.)
Subsequent work
1. Install engine carrier.
2. Install front silencer.
3. Install number plate and retainer plate.
4. Install the generator.
Fit the generator and tighten M8 external Torx screws (E12) -1, 2-.
Generator
5. Install hydraulic pump.
6. Install air conditioning compressor.
7. Install the drive belt -1-.
Slackening/tensioning the drive belt
7.1. Turn the tensioner -3- clockwise at the hexagon (a/f 30) using a ring wrench -2- and fit the belt.
7.2. Allow the tensioner to slide back to its initial position.
8. Install resonance tube.
Securing resonance tube
9. Install air cleaner housing.
10. Fill in coolant.
11. Let the engine run until warm and check for leaks.
12. Install underbody panels at the rear and left.