Programed repairs: Radiator pressure cap, Coolant pump, Fan coupling, Fan, Cooling sys. Engines 601, 602 (except 602.98), 603

Programed repairs Engines 601, 602, 603 Mechanical V

20 Radiator pressure cap

Cause/Remedy:

Pressure relieve or vacuum valve in cooling system pressure cap faulty, particularly with plastic valve plates.

Filler connection at expansion tank twisted or damaged.

1 Renew radiator cap.

2 Renew expansion tank.

P20-2171-13

20 Coolant pump

Cause/Remedy:

After vehicle has been standing for a long time, dried coolant residues in the sealing gap of the mechanical seal may cause a temporary leakage when starting.

Coolant drops which in this case flow out of the leak water passage and dry when they drop down, leave clear residue smears because of the high solids content of the coolant (6g/100 cm3)

These residue smears below the coolant pump are not an indication of a leak.

The coolant pump does not need to be renewed for this reason.

20 Fan coupling

Cause/Remedy:

Fan coupling from engine 103 installed.

Distinguishing features:

Engines 602 and 603.91

Bimetal spring; color silver grey

Imprinted part no. 603 200 00 22 (arrow).

Engine 103

Bimetal spring; color yellow

Imprinted part no. 103 200 02 22

P20-2170-13

Can be checked with mirror.

Install new fan coupling, part no. 603 200 00 22.

For reasons of space, use short pin wrench

8 mm approx. 25 mm long for slackening and tightening the fastening bolt. Use the 8 mm 3/8" square screwdriver insert part no. 103 589 01 09 00 for this step.

Pay attention to direction of rotation of fan. The cast Part No. on the fan must be at the radiator side.

Tightening torques

Fan to coupling 10 Nm,

Coupling to coolant pump 45 Nm.

20 Fan

Cause/Remedy:

If the fan is held tight when switched off and pushed slightly forward, the noise is no longer audible.

The armature ring of the magnet coupling attached to the fan by 3 leaf springs is not resting properly against the 3 mounting points at the fan.

The engine vibrations consequently cause it also to vibrate and it strikes against the contact points on the fan.

As there is no remedy at present, it may be necessary to install and listen to the behaviour of several fans.

20 Cooling system

The transmission oil cooler in the radiator is attached with aluminium collar nuts on vehicles with automatic transmission.

If these collar nuts have to be replaced in the event of a leak or damage, only steel nuts with steel washer or steel collar nuts may be used.

Tightening torque 25 Nm.

Designation Part number

Steel nut M161.5 003 990 16 51

Steel washer M16 003 990 77 40

Steel collar nut M201.5 000 990 24 50

Available from: plant 50 (PEW Sindelfingen)

Cause/Remedy:

Radiator is blocked with corrosion products.

Radiator remains cold in the middle with the result that the viscous fan coupling does not engage. See also SI 20/30.

Renew radiator.

On no account re-use anti-corrosion/antifreeze. Use only approved anti-corrosion/antifreeze part

no. 000 989 08 25.

20 Coolant pump drainage pipe

Procedure:

1 Drain coolant, pour in (20-010).

2 Remove bottom engine compartment panel, install (01-006).

3 Remove poly V-belt, install (13-342).

4 Remove crankshaft belt pulley and vibration damper, install (03-341).

5 Coat connection fitting (arrow) with adhesive and knock into the bottom vent hole at the coolant pump housing with the drift.

P20-5050-13

6 Push drainage pipe (1) onto the connection fitting using the drift (2).

Shown without dipstick guide tube

P20-5051-13

7 Push drainage (1) behind the dipstick guide tube (2). Turn bottom end of drainage pipe in the direction of the ribbing in the alternator carrier (3) so that any coolant which flows out is channelled into this ribbing.

P20-5054-15

Shop-made tool

Slugging drift.

Material: structural steel e. g. St 37-k.

P20-5062-53

Operation text and flat rates

Retrofitting drainage pipe for coolant pump (during Service Repair).

02-2028-01 Combined operation 15 work units or 1.3 hours

If replacing coolant pump

02-2029-01 Combined operation 5 work units or 0.4 hours

Parts

The drainage pipe is supplied as a parts kit.

Part no. 603 200 17 52

Cause/Remedy:

General

Since mid-October 1989 a vent pipe has been installed on these models for separating vapour bubbles in the cooling system.

Production breakpoint

Model As of vehicle ident end no.

124.128 B 108795

124.133 B 108795

124.193 F 129186

124.333 B 108795

124.393 F 128986

The vent pipe can be retrofitted to models which were produced prior to this production breakpoint if the following problems exist:

e.g. loss of heating capacity

high coolant temperatures (higher than 100 °C), without loss of coolant

coolant loss through overflow reservoir

and after

replacing engine or performing repairs to cylinder head and cylinder head gasket as a result of engine overheating

Note

Before installing the vent pipe, check whether further causes exist for this problems, e.g. check cooling system for leaks.

Vehicles affected

Model Vehicle ident end no. Engine Engine end no.

from to from to

124.128 start of prod. B 108794 602.962 start of prod. 003205*

124.133 start of prod. B 108794 603.960 start of prod. 023891

124.193 start of prod. F 129185 603.960 start of prod. 023891

124.333 start of prod. B 108794 603.963 start of prod. 001863

124.393 start of prod. F 128985 603.963 start of prod. 001863

* On engines with manual transmission from start of production up to engine end no. 000339

P20-0038-57

1. Remove bottom engine compartment panel (arrows).

2. Drain coolant completely (20-010).

3. Remove bottom coolant hose (item 9).

P01-2289-13

4. Remove air cleaner housing and air guide hose (09-400).

5. Remove coolant expansion reservoir.

6. Remove piping (item 1) at side member; detach hose connections first of all. Slacken partition panel (item 8) and raise sufficiently until pipe assembly (item 1) together with rubber seal (item 1a) can be taken off.

P20.20-0221-13

7. Unbolt cover (item 14) at the component partition by unscrewing both knurled nuts
(item a) and both expansion rivets (item b).

P01-2290-13

8. Press brake pipe for right front wheel out of the two fixtures (item 4) at the firewall.

Note

On model 250 D Turbo unbolt the two fixtures

by turning to the left and replace with new

3-piece fixtures.

Lock brake pipe in the bottom detent of the two fixtures (item 4).

P20-2126-13

9. Disconnect hose (item 6) for feed pipe to heater at heat exchanger.

P20.20-0222-13

10. Install vent pipe (item 2) by pushing pipe through at front left at brake servo unit, beginning at the firewall, and along (parallel to the brake pipe).

11. Insert vent pipe at the left-hand opening into the grommet (arrow).

P01-2287-13

12. On model 250 D Turbo, root vent pipe on the right-hand side between partition and component compartment partition (arrow).

Routing of pipe on model 250 D Turbo

P20.20-0223-13

13. On the 300 D Turbo models, make a hole (about 10 mm ) on the rear of the partition at the top recess (arrow).

Then, route vent pipe through this hole.

P01-2288-13

14. Take rubber seal (item 1a) from the removed piping and fit it onto the modified piping and install piping.

15. Connect vent pipe to piping assembly.

16. Install partition.

P20.20-0224-13

17. On model 250 D Turbo, insert protective sheathing (arrow), part no. 124 997 22 82, at the opening to the partition.

P20.20-0225-13

18. Insert vent pipe into the top detent of the two fixtures at the firewall (arrows).

P20.20-0226-13

19. Attach vent pipe to the right of the firewall with a pipe clip.

On model 250 D Turbo, pierce insulation matting at the existing hole with a suitable drift (arrow).

Model 250 D Turbo

P20-2081-13

On model 300 D Turbo, expose cutout provided (broken line).

On all models, install pipe clip with protective sheathing, M615 bolt and M6 nut (items 10, 11, 12, 13).

Model 300 D Turbo

P20.20-0227-13

20. Shorten connection hose (item 5) between coolant expansion reservoir (item 7) and piping (item 1) at the bottom end to the piping by

40 mm (L1) and fit onto piping.

21. Take the coolant level sensor out of the removed coolant expansion reservoir and install in new expansion reservoir.

L 1 = 40 mm

P20-0039-13

22. Install new coolant expansion reservoir and connect hoses.

23. Install air cleaner and air guide hose

(09-400).

P20.20-0228-13

24. Shorten the feed hose (item 6) at the disconnected end by 30 mm (L2). Fit the section cut off onto the pipe connection of the heater box.

Then, once again shorten the feed hose by

25 mm (L1).

L1 = 25 mm

L2 = 30 mm

P20-0040-13

25. Insert distributor (item 3) into the feed hose and connect vent pipe.

P20.20-0229-13

26. Install cover (item 14) at firewall.

27. Install new bottom coolant hose (item 9).

28. Install engine compartment panel.

29. Pour in coolant (20-010).

30. Check cooling system for leaks.

Operation text and time allowance

Model 124.128/133/193/333/393

Retrofitting vent pipe for cooling system

02-2024/01 basic work 36 work units or 3.0 h.

02-2025/01 corrected work 33 work units or 2.8 h.

The book/column number of the appropriate model should be added as a prefix to the operation number.

Parts

Qty. Designation Part no. Required for models

250 D Turbo 300 D Turbo

1 Coolant expansion reservoir 124 500 11 49 X X

1 Coolant hose 124 501 48 82 X -

1 Coolant hose 124 501 49 82 - X

1 Piping assembly 124 830 24 15 X X

1 Vent pipe 124 830 28 15 X X

1 Distributor pipe 124 830 26 15 X X

2 Hose clip 916026 020001 X X

1 Fixture 108 995 05 20 X X

2 Fixture 201 995 02 65 X X

1 Protective sleeving 124 997 22 82 X X

1 Protective sleeving 126 328 01 81 X X

1 M615 hexagon bolt 000933 006207 X X

1 M6 nut 003 990 08 51 X X