70012 engine cooling system

ine Csolin ystem - 20

ngine Cooling System 2 0

Job No.

Coolant circuit and engine cooling .......................................... 20 - 005Engine coolant replacement - Antifreeze table ................................. 20 - 010Cleaning and flushing cooling and heating system .............................. 20 - 015Removing oil from cooling and heating system ................................. 20 - 016Checking cooling system for leaks ......................................... 20 - 017Removal and installation of thermostat ...................................... 20 - 110Removal and installation of coolant pump .................................... 20 - 210Notes on coolant pump ................................................. 20 - 215Removal and installation of coolant pump housing .............................. 20 - 230Temperature-controlled viscous fan coupling .................................. 20 - 310Removal and installation of viscous fan coupling ............................... 20 - 312Magnetic fan coupling .................................................. 20 - 330Removal and installation of magnetic fan coupling .............................. 20 - 335Removal and installation of radiator ......................................... 20 - 420Repairing radiator ..................................................... 20 - 425Testing radiator or expansion tank cap ...................................... 20 - 430Testing coolant level indicator ............................................. 20 - 440Function of coolant level indicator .......................................... 20 - 445Removal and installation of overflow tank ..................................... 20 - 450

--

20 1

20-005 Coolant circuit and engine cooling

Coolant circuit engine 602.91

\ ._.~~ _-._

PM-0091.55

1 Expansion tank2 Overflow line3 From cylinder head to radiator4 Return from heating system (heat exchanger)6 Feed to heattng system (heat exchanger)

91213

A.B.C.D.

From radiator to coolant pump via thermostatFllllng hoseVent line

Radiator clrcult above 100 “CBypass clrcutt up to 85 “CCool waterHeatrng

20.10 - 005/l

Coolant circuit engine 602.96, 603.96

P20-0106-S

1 Expansron tank2 Overflow lrne3 From cylrnder head to radiator4 Return from heatrng system (heat exchanger)5 Fuel heat exchanger6 Feed to heating system (heat exchanger)7 Heat exchanger8 Thermostat

9 From radiator to coolant pump via thermostat10 Overflow tank (engtne 603.96)11 Radrator12 Fllltng hose13 Vent line

A.6.C.D.

Radrator crrcurt above 100 “CBypass clrcult up to 85 “CCooled waterHeating

NoteEngine 603.96 has an overflow tank (10) inaddition to the expansion tank. The overflow tankis installed in the wheelhouse of the right frontfender.

20.10 . 005/2

Function of overflow tank

The overflow tank protects the engine from lossof coolant at high outside temperatures. Coolantmay flow out along the overflow line aftershutting off the engine at high outsidetemperatures.

The coolant overflow is collected in the overflowtank.

After the engine and the coolant has cooleddown, a vacuum is produced in the coolingsystem which causes the coolant which hasflowed into the overflow tank to flow back intothe expansion tank.

To enable the vacuum to build up after coolingdown, the cap of the expansion tank mustprovide a tight seal.The cap (1.4 bar) is fitted with a rubber seal forthis purpose.

P20-217513

Function of coolant thermostat

Engine I Start of opening “C I Fully open “C

602 I 85 ,+ 2 I 100

602.96, 603.96 I 80 + 2 I 94

20.10 - 005/3

NoteThe function of the coolant thermostat is outlinedin the description below, using, as an example, anaturally aspirated engine.

Warm-up period - coolant temperature up toapprox. 85 OCUp to a coolant temperature of approx. 85 “Cthe main valve is closed and the bypass plate isfully open. The flow (B) from the radiator is thusinterrupted. The coolant flows through thebypass passage (C) directly through the coolantpump into the crankcase (D).

C From crankcase (bypass passage)D To crankcase

Part-load operation - coolant temperatureapprox. 85 OC up to maximum 100 OCAt coolant temperatures above approximately85 - 100 O C the main valve and bypass plate aremostly open, depending on engine load. Thecoolant flows from the radiator (B) through thebypass passage (C) through the coolant pumpinto the crankcase (D).

I3 From radiatorC From crankcase (bypass passage)D To crankcase

Full-load operation - high outsidetemperature (coolant at above 100 OC)At coolant temperatures above approx. 100 “Cthe main valve is fully open. The bypasspassage (C) is sealed off by the bypass plate.The entire quantity of coolant flows through theradiator.

The cooling system is automatically bled througha ball valve in the coolant thermostat when it isfilled during engine operation.

DP20-0094-13

DP20-0093-13

P20-0092-13

20.10 - 0054

ngine coolamt replacement - Antifreeze table

Preceding work:Engine compartment covertng bottom removed (01-006).

fvo-oi la57

Heater switch .......................... set to maximum heating capacity.Cap(8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . remove, refit.

A WarningOpen cap only when coolant temperature isbelow 90 OC.

Drain plug (1) . . . . . . . . . . . . . . . . . . . . . . . . . . open, close, 1.5 - 2 Nm, drain coolant (step 2).Drain plug (12) and drain connection . . . . . . . . . open, close, 30 Nm, drain coolant (steps 3, 4).Old coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . flush out.Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pour in up to marking on expansion tank (10)

(step 6).Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . run until coolant thermostat opens, approx. 90 -

100 “C (step 7).Coolant level . . . . . . . . . . . . . . . . . . . . . . . . . . check (step 8).Cooling system . . . . . . . . . . . . . . . . . . . . . . . . check for leaks (20-017).

20.10 - 010/l

Total capacities of cooling system with heating system and mixing ratio of anti-corrosion/antifreeze agent’) and water-n) in liters

Model Engine Total capacity of cooling systemwith heating system

124 602.96 8I

124, 126 (603.96/97 I10

201

Mixing ratio anti-corrosion/antifreezeagent/water for antifreeze prot. down to-30 “C -45 “C

3.514.5 4.513.5

4.515.5 5.514.5

3.514.5 4.5i3.5

l) See Service Product Speclflcations sheet 325.1 and 325.22) See Sewce Product Speclflcatlons sheet 310

Tightening torques Nm

Radiator drain plug 1.5 - 2

Crankcase drain plug 30

Drain connection (engine 602 and 603 only) 30

Special tools

001 589 72 21 0000 /

Commercial tool

Antifreeze protection testerPrestone-W-Check (Union Carbide)

e.g. Ph. Gather,4020 Mettmann

20.10 - 01012

Notes, see VOI Environmental ProtectionCatalog

WaterUse water which is clean and not too hard.Usually drinking water satisfies theserequirements. The content of dissolvedsubstances in the water may result in corrosion.

Anti-corrosion/antifreeze protectionThe anti-corrosion/antifreeze agent must performthe following tasks:- Adequate corrosion and cavitation protection

for all components- Antifreeze protection- Provides increased boiling point

50% by vol. anti-corrosion/antifreeze agent mustbe added to the water. This concentration offersantifreeze protection down to approx. -37 “C.A higher concentration is only recommended forvery low ambient temperatures.

More than 55% by vol. anti-corrosion/‘antifreezeagent reduces the antifreeze protection andreduces the heating capacity.

55% by vol. anti-corrosion’antifreeze agentoffers antifreeze protection down to approx.-45 O C. Anti- corrosion/antifreeze agentincreases the boiling point, in other words thecoolant does not evaporate so rapidly. Thisavoids coolant being lost at high coolanttemperatures.

Use only approved anti-corrosion/antifreezeagents (see Service Product Specificationssheets 325.1 and 325.2).

20.10 - OlOf3

Operational monitoring of coolantCheck the coolant for resistance to low tempera-tures at the start of the cold season of the year.Check anti- corrosion/antifreeze agent concen-tration once a year in areas with high outsidetemperatures.

When adding coolant (after loss of coolant), itmust be assured that there is an anti-corrosion/antifreeze agent portion of 50% by vol. in thecoolant to provide antifreeze protection down to-37 “C.

The anti-corrosion protection in the coolant isreduced over the period of operation. Thecoolant then has a sharply corrosive effect.The maximum permissible period of use of thespecified coolant in car engines is 3 years.Before adding fresh coolant, the used coolantshould be first flushed out of the system.

Draining

1 Set heating switch to maximum heatingcapacity.

2 Open cap on expansion tank in stages, allowsystem pressure to escape and remove cap.A WarningOpen cap only when coolant temperature isbelow 90 “C.

3 Open drain plug on the radiator.

NoteAn extension hose can be fitted to the drainconnection for collecting coolant.

Installation instructionTightening torque 1.5 - 2 Nm.

Drain plug on models wlthout air conditioningP20-2043-13

20.10 - 01014

Drain plug on models with air condltloning

On models with air conditioning, open flap fortowing lug at front right of lower bumper molding.

1 Drarn plug on models with aircondltlonrng

NoteOn models with air conditioning, the plug belowthe right side wheelhouse at the noise encapsu-lation should be removed. An extension hosecan be fitted onto the drain connection of theradiator through this opening.

Extension hose fltted on (with air condltionlng)

4 Unscrew drain plug (12) on crankcase.

Installation instructionTightening torque 30 Nm.

20 10 - 010/5

NoteEngines 602 and 603 have a drain connection(12a) in place of the drain plug. A hose can befitted onto this drain connection for draining.

Installation instructionTightening torque 30 Nm.

Filling in coolant

5 Flush out old coolant.

6 Slowly pour in coolant up to the marking(arrow) on the expansion tank.

Marking on expamon tank

NoteThe filler hose can be pressed down (arrow)when adding coolant to ensure that it flows morequickly from the expansion tank into the radiatorand engine.

7 Run engine until the coolant thermostatopens (coolant temperature approx.90 - 100 “C).

NoteClose filler connection at expansion tank from acoolant temperature of approx. 60 - 70 “C.

8 Check coolant level; top off to specifiedmarking, if necessary.

P20 - 2032 - 13

9 Check cooling system for leaks (20-017).

20.10 - 010.6

20-015 Cleaning and flushing cooling and heating system

Preceding work:Engine compartment covering bottom removed (01-006).Coolant drained (20-010).

e?o-o11i_x57

Coolant thermostat ......................

Flushing connection pipe (01) . . . . . . . . . . . . . .

Cooling system ........................

Cooling system expansion tank .............

Cooling system ........................

remove and install forcibly-opened thermostatPart No. 000 589 74 63 00 (step 1).install and connect tap water hose (03)(steps 2 and 3).

flush (step 4 - 20, 22).

remove and install, flush out (step 21).

check for leaks (20-017).

Service productsAnti-corrosion/antifreeze agent 000 989 08 25

Citric acid powder (0.5 kg) 000 989 10 25

20.10 - 0151

Special tools

117 589 00 9020 00 I

NotesHigh coolant temperatures and low heatingcapacity may also be caused by deposits ofcorrosion products in the radiator and in the heatexchanger.

The deposits are recognizable as a jelly-likemass or, when the radiator is empty and dry,from a grey layer on the cooler connectionpipes.

In this case, the cooling and heating system canbe cleaned with a 10Y0 citric acid solution.

Radiators which have cooling pipes which arefully or partially clogged, must be replaced.

Scope of flushing operation

1 Remove coolant thermostat and installforcibly-opened thermostat 000 589 74 63 00with sealing ring.

20.10 - 01512

2 Connect flushing connection pipe Part No.117 589 00 90 00 with connection hose betweenradiator and coolant hose.

3 Connect a tap water hose to the flushingconnection pipe.

4 Open cap of expansion tank.

5 Set heater to “warm”.

Models with auxiliary heater6 If automatic heating control is fitted, set thetemperature selectors to “Max” or, if automaticclimate control is fitted, press the “Defrost”button so that the circulation pump is switchedon when the engine is running.

7 Open bleeder valve of the auxiliary heater.

8 Flush cooling and heating system withflowing water for approx. 5 minutes with theengine running (approx. 2500 rpm) so that theremaining coolant is flushed out.

Caution!During the flushing operation, the cooling systemmust always be completely filled. Adjust feedquantity accordingly.

9 Allow flushing water in the radiator andcrankcase to completely drain out. Screw indrain plugs at radiator and crankcase.

10 Dissolve 15 kg citric acid powder (0.5 kg,Part No. 000 989 16 25) in 5 liters of water in asuitable vessel.

11 Pour cleaning solution into the coolantexpansion tank and top off with water as far asthe marking on the expansion tank.

12 Close bleeder screw of auxiliary heater.

13 Close cap of expansion tank.

20.10 - 01x3

14 Run engine for 15 minutes at approx.2500 rpm. The solution must flow through theheat exchanger (step 5).

15 Following this, drain cleaning solution.

Caution!Empty the cleaning solution (citric acid mixture)into a standard workshop oil and waterseparator.

16 Open the bleeder screw of the auxiliaryheater.

17 Flush cooling and heating system for approx.10 minutes with flowing water with enginerunning (2500 rpm). The water must flow throughthe heat exchanger (see steps 5 and 8).

18 Remove flushing connection pipe andconnect coolant hose to the radiator.

19 Install normal coolant thermostat with newseal.

20 Screw coolant drain plugs into radiator andcrankcase.

21 Remove coolant expansion tank, flush outonce again separately, and install.

NoteThe cleaning solution is not completely removedwhen drained because of pockets or recesses inthe coolant expansion tank.

22 If car fitted with auxiliary heater, connectplastic hose to bleeder valve and open valve.

23 Add fresh coolant (20-010).


20.10 - 01!34

............................................................................................ ............................ ........ ... ............

20-016 Removing oil from cooling and heatfng system

Preceding work:Coolant drained (20-010).Coolant thermostat removed (20-l 10).

f-fester control .........................

Cooling system ........................

Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flushing solution ........................

Cooling system . . . . . . . . . . . . . . . , . . . . . . , . check for leaks (20-017).

set to “warm” (step 1).

fill with a 5 % flushing solution (step 2).

warm up to normal operating temperature andrun for approx. 5 minutes (step 3).

drain and fill cooling system twice with freshwater, run engine each time for approx. 5minutes, completely drain flushing solution(steps 5 and 6).

20.10 - 016/l

Special tool

124 589 15 21 00\ 20 /

NoteOil must be removed from the cooling system ifengine oil, automatic transmission fluid onmodels fitted with automatic transmission, orhydraulic oil entered the cooling system.

Removing oil

1 Set heater control to full capacity.

Caution!On vehicles with light alloy radiators, strongalkaline cleaners such as P3 Standard (supplier:Henkel) must not be used.

2 Fill the cooling system with a 5 % solution ofwater and neutral cleaner or with a mild alkalinecleaner such as 3-Croni (supplier: Henkel) orGrisiron 7220 (supplier: Farbwerke Hoechst).

3 Warm up engine to approx. 80 “C byrunning at moderate rpm and maintain forapprox. 5 minutes at this temperature.

4 Switch off engine and allow cooling systemto cool down to approx. 50 “C.

5 Drain solution completely.

6 Immediately following this step, fill coolingsystem twice with fresh water, warm up engine(approx. 5 minutes) and drain.


20.10 - 016/'2

20-017 Checking cooling system for leaks

Pressure cap . . . . . . . . . . . . . . . . . . . . . . . . . . open in stages, allow system pressure toescape and remove.

AWarningThe pressure cap must only be opened if thecoolant temperature is below 90 “C.

Coolant level . . . . . . . . . . . . . . . . . . . . . . . . . . must extend up to the mark on the expansiontank (10).

Heater switch . . . . . . . . . . . . . . . . . . . . . . . . . . set to maximum heating capacity.

Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 589 15 21 00, attach to expansion tank (10)and pressurize cooling system, approx. 1.4 bargauge pressure.Check all cooling and heating hoses and theirconnection points for loss of coolant. Checkcondition of hose clips, tighten if necessary.

20.10 - 017/l

Special tool

Commercial tool

7 mm wrench socket on flexible shaft for hoseclips with worm drive

e. g. Hazet,D-5630 RemscheidOrder No. 426-7

Checking for leaks1 Turn cap to 1st detent and allow systempressure to escape, then turn to 2nd detent andremove cap.

A, WarningThe pressure cap must only be opened if thecoolant temperature is below 90 “C.

2 The coolant level must extend up to themarking on the expansion tank (arrow).

3 Pressurize cooling system with the tester124 589 15 21 00 (approx. 1.4 bar).

4 Check all cooling and heating water hosesand their connection points for loss of coolant.

Check that hose clips are in proper conditionand correctly seated, replace or tighten asnecessary.

20.10 - 017('2

emoval and installation of thermostat

Precedmg work:Coolant drained (20-010).

321

Housing cover (320) . . . . . . . . . . . . . . . . . . . . . unscrew from coolant pump, screw on, bolts(321) 10 Nm. Replace seal (319).

Thermostat (318) . . . . . . . . . . . . . . . . . . . . . . . check. Make note of installation position; therecess on the thermostat must be aligned withthe rib in the thermostat housing cover.NoteThermostat and thermostat housing cover aremarked with a green dot on turbo engines.

Special tool

001 589 72 21 0000 /

20.10 - 1101'1

emoval and installation of coolant pump

Preceding work:Coolant dralned (20-010).Radiator removed (Model 201 .126 only) (20-420).Poly V-belt removed (13-342).

346344

w299a

Engine 602, 603:Fan with viscous fan coupling (295) . . . . . . . . . . unbolt, bolt on, hexagon socket bolt (297), 45

Nm.Use screwdriver 103 589 01 09 00,torque wrench 001 589 66 21 00 andcounter holder 603 589 00 40 00 (step 2).

Belt pulley (299, 346) . . . . . . . . . . . . . . . . . . . . unbolt, bait on. Hexagon socket bolts (299a), 10Nm, Torx screws (345), 15 Nm(step 3).

20.10 - 21011

Caution!The magnet carrier must not be removed.

Engine 601: Remove cable, unbolt hexagon nut (349a) andMagnet body (347) . . . . . . . . . . . . . . . . . . . . . remove magnet body (steps 4, 5).

Coolant pump (300) . . . . . . . . . . . . . . . . . . . . . unbolt, bolt on, replace hexagon bolts (308), 10Nm. Replace gasket (307), clean sealingsurface.


Hexagon bolts of fan 25

Hexagon socket screws of viscous fan coupling 45

Hexagon bolts of coolant pump 10

Hexagon socket screw of belt pulley 10

Torx screw of belt pulley 15

Special tools

001 589 72 21 0000

001 589 66 21 0000

I

603 589 004000 103 589 01 09 0020 20

20.10 - 21012

Removal

Engine 602, 6032 Detach fan cowl, place over the fan.Unscrew viscous fan coupling, using screwdriverinsert 103 589 01 09 00 (03) torque wrench001 589 72 21 00 (02) and counter holder603 589 00 40 00 (01).

3 Unbolt hexagon socket bolts (345) andremove belt pulley (346).

NoteThe magnet carrier (348) is bonded to thecoolant pump housing and must not be removed.

6 Unbolt coolant pump.

7 Clean sealing surfaces.

20.10 - 210/3

Installation

8 Insert coolant pump with new gasket andtighten hexagon bolts.

Tightening torque 10 Nm.

9 Install magnet body and plug in cable.

10 Install belt pulley.

Tightening torqueHexagon socket screw 10 Nm,Hexagon socket torx screw 15 Nm.

The remaining parts are installed in reverseorder.

2 0 . 1 0 - 2 1 0 1 4

... .......................................... ........ .....

m-21 5 Notes on coolant pump

General

The coolant pump located at the bottom right ofthe engine is attached to a light alloy housingbolted to the crankcase. The coolant thermostat(318) is also contained in this housing.

A flange (302) is pressed onto the coolant pumpshaft (303) for attaching the belt pulley. Anexpansion space (E) is located between coolantpump bearing (304) and cassette seal (305). Thefan is attached at the stub end (arrow).

301302303304305306307308

316317318319320BCDE

Coolant pump housingFlangeCoolant pump shaftCoolant pump beanngCassette sealImpellerGasketHexagon boltM 6x35Fit punLight alloy housingCoolant thermostatGasketInlet connectlonInlet connectlon to radiatorPump chamberInlet from crankcaseExpanston space

P20-0090-35

20 10 - 21511

296 -

Engine 602 and 603Arrangement of VISCOUS fan coupkng and coolant pump

5 Ball beanng295 Fan296 3 bolts M 6 X 14

’ 297 Hexagon socket screw M 10 X 40298 VISCOUS fan coupling301 Coolant pump housing345 4 hexagon bolts M 6 x 12346 Belt pulley

The coolant pump of engine 602 and 603 isstrengthened at the coolant pump housing (301)and at the coolant pump bearing (304) becauseof the heavier viscous fan coupling.

The diameter of the impeller (306) on all theengines is identical.

The coolant pump shaft has a tapped holeM 10 X 22 at the front for attaching the viscousfan coupling.

297-

5-

298-

306

I I304 E 303 P20-0096-13

301 Coolant pump housrng302 Flange303 Coolant pump shaft304 Coolant pump beanng305 Cassette seal306 Impeller316 Fit sleeveE Deformatton space

20.10 - 215;2

20-230 Removal and installation of coolant pump housing

Preceding work:Coolant pump removed (20-210).Alternator removed (15510)

321

415

Pzo-o101-57

Ground cable to battery . . . . . . . . . . . . . . . . . . . disconnect, connect.

Supporting bracket for alternator (416) . . . . . . . . unbolt, bolt on, hexagon bolts (417, 420) 25Nm.

Return lines (326,326 a) . . . . . . . . . . . . . . . . . . unbolt at crankcase, bolt on, withdraw fromcoolant pump housing (317) insert. ReplaceO-ring (325).

Caution!Do not coat O-ring with oil or grease; use onlyantifreeze.

Engines 602.96, 603.96 with automatictransmission:Cable from temperature switch . . . . . . . . . . . . . detach, plug in.

Temperature switch . . . . . . . . . . . . . . . . . . . . . unscrew, refit.

20.10 - 230/l

Coolant pump housing (317) . . . . . . . . . . . . . . . unbolt, bolt on, hexagon bolts (352),10 Nm. Clean sealing surface and replacegasket (315).

Cooling system . . . . . . , . . . . . . . . . . . . . . . . . check for leaks (20-017).


Hexagon bolts of coolant pump housing 10

Hexagon bolts of supporting bracket for alternator 25

Hexagon bolts of alternator 45

Special tools

001 589 72 21 0000 /

Removal

I 001 589 00 66 21 00

1 Disconnect ground cable at the battery.

2 Unbolt supporting bracket for alternator(arrows).

3 Unbolt return line (326) at the crankcase andwithdraw from the coolant pump housing.

20.10 - 23012

...........................................................

Engines 602.96 and 603.96 with automatictransmission:4 Detach cable for temperature switch incoolant pump housing and unscrew temperatureswitch.

5 Unbolt coolant pump housing.

6 Clean sealing surfaces.

Installation

7 Replace O-ring on return line.

NoteKeep O-ring free of grease. The O-ring can bedipped in coolant to ease installation.

8 Fit coolant pump housing onto the return lineand install onto crankcase with a new gasket.


9 Bolt return line onto the crankcase.

10 Install supporting bracket for alternator (419)and tighten fastening bolts.


11 Connect ground cable to the battery.


20.10 - 2300

20-310 Temperature-controlled viscous fan coupling

Function

The viscous fan coupling is a maintenance-freehydraulic coupling which operates proportionatelyto temperature.

When the engine is started (cold start), the faninitially runs at a higher speed until the oil hasflowed back from the working chamber (B) intothe storage chamber (A). Following this, the fancoupling shuts off. Fan speed in the off statedepends on engine speed. Fan speed, in anycase, does not exceed 1000 rpm.

This state is maintained until the engine hasreached the fan activating temperature.

23456789AB

68

7

Coupling body (secondary part)CoverDrlvlng plate (pnmary part)Switch pinBall beartngBeanng bushBtmetal stripSealValveStorage chamberWorking chamber

20.10 . 310/l

If the coolant temperature rises due to higherengine loads or high outside temperatures, thearr which flows through the radiator and contactsthe bimetal strip (7) becomes warmer. Thebimetal strip (7) alters its shape as It heats upand opens a valve (9) at approx. 71 “C bymeans of a pin (4) and thus also the passage forthe oil from the storage chamber (A) into theworking chamber (B), which causes the fan toactivate.

The coolant temperature during this switchingoperation remains between approx. 90 and 95“C.

When the coupling IS engaged, fan speedincreases proportronally with increasing enginespeed In the lower rpm range, without exceeding3300 rpm in the upper range.

89A6

Checking activation temperatureRun engine at 4000 - 5000 rpm. Once a coolanttemperature of approx. 90 - 95 “C has beenreached, the speed of the viscous fan couplingmust increase, which can be clearly heard.

n

68

7

P2l%oo97-15

Coupling body (secondary par-t)CoverDnvlng plate (pnmary part)Switch pinBail bearingBeanng bushBlmetal stnpSealValveStorage chamberWorking chamber

RepairIt is not possible to repair a defective coupling; itmust be replaced.

20 10 - 310 2

Transportation and storageTemperature-controlled viscous fan couplingsmust be transported upright. For brief periods -e. g. for installation purposes, the coupling maybe placed on the flange side, but never on thefront side.

Caution!The bimetal strip must not be bent or damaged.

Distinguishing featuresEngine 602.911 bimetal spring; color silver grey.Imprinted Part No. 603 200 00 22 (arrow).

The viscous fan couplings of engine 602.96 and603.96 have been strengthened to compensatefor an enlarged fan.Bimetal spring; color metal-colored.Red imprinted Part No. 603 200 04 22.

PM2174-13

20.10 - 31013

20-312 Removal and installation of viscous fan coupling

Preceding work:Radiator removed - only Model 201.126, 124.133, 124.193(20-210).

P20-0104-55

Hose holder (15) ....................... unclip, clip in.Retaining clip (1) ....................... pull off, fit on.Fan cowl (11) .......................... place over the fan.

Caution!Separate split fan cowls and remove.

Hexagon socket screw (297) . . . . . . . . . . . . . . . unscrew, screw in, 45 Nm, using screwdriverinsert 103 589 01 09 00, torque wrench001 589 72 21 00 and counter-holder603 589 00 40 00 (step 3).

Fan (295) with viscous fan coupling (289) . . . . . . remove at coolant pump (300) insert.Fan (295) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . unscrew, screw on, hexagon socket screw

(296), 10 Nm.

Caution!Notice direction of rotation of fan (295).Inscription must be facing direction of travel.

20.10 - 312/l


Hexagon socket bolts of fan 10

Hexagon socket screw of VISCOUS fan coupling 45

Note I

As a distinguishing feature on engines 602 and603.91 a silver-colored sticker with Part No.603 200 00 22 and 603 200 04 22, respectively,is attached to the viscous fan coupling. A redinscription appears on the same part for engine603.96.

P20-2174.13

The hose holder for attaching the vent hose atthe fan cowl has been modified from a single-section version to a two-section version.

A Previous versionB Present version

20.10 - 312 2

Production breakpoint: 10187 - OY88

. not reglstered

Special tools

103 589 01 09 00 603 589 00 40 00

Removal

1 Remove clip together with vent line from fancowl (arrow).

2 Pull off retaining clips (1) for fan cowl. Placefan cowl over the fan.

20.10 - 312/3

3 Unbolt viscous fan coupling with torquewrench 001 589 72 21 00 (02) and screwdriverinsert 103 589 01 09 00 (03). Hold the beltpulley with the counter-holder603 589 00 40 00 (01) when performing thisstep.

4 Remove viscous fan coupling together withfan and fastening bolt.

5 Unbolt fan from the viscous fan coupling.

Installation

Caution!Notice direction of rotation of fan. Marking mustbe pointing in direction of travel.

6 Bolt fan onto the viscous fan coupling.


7 Fit fan with viscous fan coupling andfastening screw onto the coolant pump.

8 Tighten the hexagon socket bolt withscrewdriver insert 103 589 01 09 00 (03) andtorque wrench 001 589 72 21 00 (02). Hold thebelt pulley securely with the counter-holder603 589 00 40 00 (01) when performing thisstep.


9 Install fan cowl.

10 Attach vent line at fan cowl.

P20-2172-13

2 0 . 1 0 - 312,/4

20-330 Magnetic fan coupling

The magnetic fan coupling is activated by a 100“C temperature switch (S2511) mounted at theoutlet connection.

The electromagnetic fan coupling ismaintenance-free.

Design of the electromagnetic fan couplingThe magnet body (347) is attached to themagnet carrier (348) with 3 nuts (349).

The magnet carrier is bonded to the coolantpump housing and does not need to beremoved.

302 Flange303 Shaft304 Bearing305 Cassette seal306 Impeller309 Tensioning plate317 Coolant pump housing340 Collar bolt341 Washer343 Beanng344 Fan344a Armature344b Leaf spnng345 Hexagon socket screw M 6 x 12346 Belt pulley347 Magnet body348 Magnet carrier349 Hexagon nut

U II

344 344a

r-t44

I UUII~-+---346 317

341

345302

306

20.10 - 330/l

The electric cable is connected to the magnetbody (347) via a coupling (arrow).

The belt pulley (346) is mounted to the coolantpump shaft in front of the magnet body.

The belt pulley (346) is bolted to the flange ofthe coolant pump with 4 hexagon socket bolts(345) or torx bolts.

Function

The fan is activated only if the ignition is turnedon and the coolant is at a temperature above 98- 102 “C.

Voltage is applied constantly to the magnet body(347) through fuse No. 10 terminal 15 (1 stversion).

Below a coolant temperature of 98 - 102 “C thefan is switched off and only rotates as a result ofair flow over the fan when the vehicle is moving.

A negative voltage is applied by the temperatureswitch in the outlet connection at no less than acoolant temperature of 102 “C.

3 4 4 t343.309.340341

345.302.

344 344aI

-mr- -7-l

111 I I iW-346 317

+?=-Y 3 0 4 L-=-J

306

305

-l----II m,) 349 303-

P20-0089- 15

2 0 1 0 - 3 3 0 2

The armature (344a) is attracted by the magnetbody (347) and presses against the face of thebelt pulley (346).

The fan becomes rigidly attached to the beltpulley and rotates at coolant pump speed.

If the coolant temperature drops below 93 -98 ‘C, the temperature switch opens and thearmature is lifted off the belt pulley (346) by leafsprings (344b).

On vehicles with air conditioning, the fan andelectric auxiliary fan are activated through adouble contact relay which is activated by the 52“C temperature switch at the fluid reservoir.

If the air conditioning is off, the 100 “Ctemperature switch at the outlet connectionalone engages or disengages the fan.

The armature (344a) and the ball bearing (343)are fitted to or to the inside of the fan.

The ball bearing is sealed on both sides withcover plates.

Fan

The fan (A) has 6 blades and a diameter of380 mm.

On vehicles with air conditioning, the fan (8) has5 blades and a diameter of 430 mm.

20.10 - 33013

Modification to electromagnetic couplingModel 201Effective 10 84 a modified electrical center hasbeen installed. As a result, the electromagneticcoupling is operated by a positive voltagethrough a 2-pin temperature switch (S25 1)(previously negative voltage).

\- \ I I

1 D1 \ IPm-3165.13

\I

On vehicles with air conditioning positive isconnected through a relay also after thepressure switch (14) closes.

2010. 330’4

............................................................... ................................................... .....

20-335 Removal and installation of magnetic fan coupling

Precedtng work:Poly V-belt removed (13-342).

1

Retaining clips (1 a) . . . . . . . . . . . . . . . . . . . . . . remove, refit.Fan cowl (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . detach, attach, place over fan.Fan (344) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . unbolt, bolt on, 25 Nm.Belt pulley (346) . , . . . . . _ . . . . . . . . . . . . . . . . unbolt, bolt on, hexagon socket bolt

10 Nm or torx screw 14 Nm.Magnet body (347) . . . . . . . . . . . . . . . . . . . . . . pull off cable connection, fit on, unbolt nuts

(349a), bolt on.Magnet carrier (348) . . . . . . . . . . . . . . . . . . . . . do not remove from coolant pump, check for

tightness, secure with adhesive001 989 45 20 10, if necessary.

Special tools

001 589 72 21 0000

20.10 - 33511

20420 Removal and installation of radiator

Preceding work:Bottom engine compartment coverlng removed (01-006).Coolant drained (20-010).

P20-0119-57

Vehicles with automatic transmission:Oil lines at cooler .......................

Holder (15) ...........................

Flat spring (1) ..........................

Fan cowl (11) ..........................

Coolant hoses (10, 14) . . . . . . . . . . . . . . . . . . .

Expanding rivets (5) .....................

Radiator coverings (6, 7) ..................

unbolt, bolt on, clamp with special tool000 589 40 37 00 (step 1).

for vent hose, unclip, clip in (step 4).

remove, insert.

remove, insert. Place fan cowl (11) over the fan.

detach, attach, check condition.

remove, insert (step 5).

remove, install.

20.10 - 42011

Retaining clip (4)

Model 201.128Radiator bridge

Model 201.128Front bumper .

. .

. .

. .

. .

I .

.................... pull off, fit on.

. . . . . . . . . . . . . . . . . . . . unbolt, on.

.................... remove, attach (88-200).

Evaporator ............................ unbolt from radiator, screw on.

Flat spring (2) .......................... withdraw, insert.

Radiator (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . lift out, insert.

Cooling system ........................ check for leaks (20-017).

Installation dimensions for radiator, fan and fan cowl

l) Two-section fan cowl

20.10 - 420:2

PO3- 0138 -15

Radlator’fan Fan/fan cowl

Special tool

.

Commercial tool

7 mm wrench socket on flexible shaftfor hose clips with worm drive

e. g. liazet,D-5630 RemscheidOrder No. 426-7

20.10 - 4200

Removal

Vehicles with automatic transmission:1 Clamp orl lines at automatic transmissionwith special tool 000 589 40 37 00, moving thespiral spring slightly to the side and unscrewingat the radiator.

2 Seal off coolant hoses at the radiator.

3 Withdraw hose holder (15).

4 Pull out flat springs (1) for fan cowl, raisecowl slightly and place over the fan.

5 Remove the expanding rivet (5) on the rightand left side for the side radiator covering.

6 Remove radiator coverings.

7 Remove the retaining clip (4) at the bottomright and left.

1 \ POl-2373-13

\

P20-2166-13

20.10 - 42014

Model 201.1288 Unbolt radiator bridge (arrows).

NoteThe front bumper must be removed on vehicleswith air conditioning in order to be able to unboltthe evaporator from the radiator(88-200).

Pm2112.13

9 Withdraw flat springs (2) for radiator and liftout radiator.

Installation

Installation is performed in the reverse order.

NoteEnsure that the fixing mounts of the radiator arecorrectly positioned into the rubber grommets ofthe bottom holders and that the holders of thefan cowl are correctly inserted into the retainingclips on the radiator (arrows).


2 0 . 1 0 - 420/5

epairing radiator

Preceding work:Radiator removed (20-420)

P20 - 0 0 7 1 - 3 5

Radiator honeycomb (1) . . . . . . . . . . . . . . . . . . check for signs of damage.

Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . clean and seal hose connections and oil coolerline (steps 1 - 4).

Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pressure test with tester 124 589 15 21 00 and605 589 00 25 00 in water bath, mark leakpoint, reduce pressure and blow-dry radiatorwith compressed air (steps 5 - 10).

Top and bottom water tanks (3, 4) . . . . . , . . . , . check for leaks.

Gasket (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . check for leaks.

Radiator , . . . , . , . . , . . . . . . . . . . . . . . . . . . . . seal leak point with repair kit radiator sealant123 989 00 20 (steps 11 - 15).

A WarningNote safety instructions!

20.10 - 425/l

Radiator .............................. pressure-test at 1.4 bar gauge pressure in waterbath, check for leaks (steps 16 - 17).

Radiator .............................. install (20-420).Cooling system ........................ check for leaks (20-017).

Sealant

Repair kit radiator sealing 123 989 00 20

Special tools

Commercial tool

7 mm wrench insert with flexible shaftfor hose clips with worm drive

e. g. Hazet,D-5630 RemscherdOrder No. 426-7

Shop-made tool

Cap for top hose connection:

15 2 clips L 3646, Part No. 916026 03600016 Piece of hose, Part No. 201 501 38 8217 Reducer made from two tubesA 35 mm dia.B 39 mm dlaC 12mmdla

PZO-0082- 13

20.10 - 42512

................................................... ...................................

Shop-made tool

Cap for bottom hose connection:

18 2 clips L 3646, Par-t No. 916026 03600019 Piece of hose, Part No. 201 501 38 8220 Cap from a tubeA 35 mm dta.B 39 mm dia.

18 19 18 20

P20-0072-13

Designation Use

Priming Preparation ofliquid base

Undiluted For properly sealingsealant accessible points

Dilutedsealant

For sealing difficult-to-reachpoints (e. g. sides of coolingtubes)

Sealant and priming liquid have a storage life ofapprox. 1 year provided they are always sealedairtight after use.

Priming liquid which has become cloudy shouldno longer be used.

The following parts or points in the coolantcircuit can be sealed with the sealant:

a) Plastic water tanks (3 and 4).b) Heavy metal water tanks (holes up to

1.5 mm diameter).c) Light and heavy metal cooling tubes (6).d) Tube plate (2).e) Beaded collar (connecting point between

radiator honeycomb and water tank).f) Heat exchanger of heating system.

20 10 - 42513

Fractured or cracked fastening straps or cracksat the connection fittings cannot be repaired.

Brazing or soldering on heavy metal radiatorswith plastic water tanks may only be performedon the honeycomb (1) at a distance of at least20 mm from the water tank otherwise the highbrazingsoldering temperature wtll damage thegasket (5) and the water tank (3 and 4). Leakswhich are located closer to the water tank shouldbe repaired only with sealant.

The radiator does not have to be removed fromthe vehicle for sealing. In this case, it issufficient to drain the coolant and to pressure-test the cooling system with the tester (approx.1.4 bar gauge pressure) after sealing.

Caution!Light alloy radiators with plastic water tankscannot be repaired by brazingsoldering.

Sealant is available in diluted and undiluted formin order to seal leaks of different accessibility atthe radiator (e. g. more difficult In thehoneycomb than at the water tank).

The various sealant versions and the primingliquid are combined in a repair kit Part No.123 989 00 20.

20.10 - 425,4

...................................................... .............. .....

AWarningThe priming liquid is easily combustible (notesafety instructions, Hazard ClassA 1).

Acetic acid is released until the sealant hascompletely cured. For this reason, avoid contactwith skin. Clean affected areas immediately withwater and soap. Rinse out eyes with water.Consult a doctor if necessary.

Sealing

1 If the leakage point cannot be properlylocated with the radiator installed, removeradiator (20-420).

2 Clean radiator.

3 Seal hose connections with the shop-madecaps.

4 Seal connections of the transmission oilcooler with plastic caps or plugs from old oilcooler lines. Cut off the oil cooler lines justbehind the nipple and solder on.

5 Connect testers 124 589 15 21 00,605 589 00 25 00 to the radiator.

6 Place radiator in a water bath.

7 Pressurize radiator with the tester and checklocation of rising air bubbles.

8 Mark leakage points.

9 Remove radiator and reduce pressure.P20-2153-13 I

20.10 - 425/5

10 Blow-dry radiator with compressed air.

11 Clean leakage point and area around it witha commercial cleaning agent (e. g. tri or whitespirit).

It is not necessary to remove any paint. Theradiator should then be blown-dry at the affectedpoint with compressed air.

There must not be any dust or grease residuespresent on the surface.

12 Apply a very thin and even coat of primingliquid with a brush.

Apply the priming liquid at and around the pointto be sealed. Pour the quantity of priming liquidrequired for the repair in a separate vessel toavoid polluting the entire can of priming liquid.

A WarningNote safety instructions!

13 Allow priming liquid to dry for approximately10 minutes at room temperature.

14 Apply diluted or undiluted sealant accordingto accessibility. Use brush, spatula or the like forspreading the sealant.

2 0 . 1 0 - 425/6

Caution!During application and spreading sealant, ensurethat no air is trapped.

Using the same method as for cleaning andpriming, apply the sealant not only at the point tobe sealed but also around it. If there are severalleak points at the beaded collar (arrows) it isrecommended to seal the beaded collarcompletely around its circumference.

Seal leaks in the honeycomb from both sides.

After completing the sealing procedure, closetube immediately. Acetic acid is released untilthe sealant has completely cured. Avoid contactwith skin. Clean affected areas immediately withwater and soap. Rinse out eyes with water.Contact a doctor if necessary.

15 Leave radiator upright or face-down for atleast 3 hours for the sealant to dry. Dependingon the quantity of sealant applied and the size ofthe point treated, it may take up to 24 hours forthe sealant to cure to form a permanent elasticjoint at room temperature.

16 Pressure-test radiator for approx. 5 minutesin a water bath at 1.4 bar gauge pressure.

If any leaks remain, repeat sealing operationstarting at step 8.

17 Remove testers and plugs.

18 Install radiator (20-420).


20.10 - 42W

...................................................................................................... .....................................

20430 Testing radiator or expansion tank cap

P20-01~35

Double connection 000 589 77 63 00 ......... connect to leak tester 124 589 15 21 00.

Cooling system pressure cap ............... screw onto double connection 000 589 73 6300.

Opening pressure ....................... test.

Pressure cap

Pressure cap code number I 120 140

Pressure relief valveopensat bar gauge pressure

new

used

Vacuum valve opensat bar vacuum

0.1

20.10 - 43011

NoteIf corrosion is present on the expansion tankcap, it must be replaced.

Engines 602.961, 603.960, 603.961The opening pressure of the cap has beenincreased from the previous 1.2 bar to 1.4 bar;with standard antifreeze protection down to-30 OC, the permissible coolant temperature isincreased as a result from 125 to 129 “C.

Production breakpoint: 02 - 09/86

Model

124.133124.193

126.125

201.128

Engine Engine End No. Vehicle End No.manual automatictransmission transmission A F

603.960 * * * *603.960 * * * 017987

603.961 * * * *

602.961 * * * 271512

f not registered

This cap is provided with a rubber seal (A) toprevent any outside air from being drawn in(when vacuum exists in cooling system).

P20-0107-13

20.10 - 430/2

Effective 1 O/87 and 12/87, respectively, pressurecaps with and without guide ring (B) have beenfitted to engines 602, 603. Only the pressure capwith guide ring is supplied as a replacement part,however.

The modified pressure cap can also be fitted tovehicles manufactured previous to productiondates with coolant expansion tank.

A Seal8 Guide rr-tg

Special tools

Testing pressure relieve valve

1 Attach double connection 000 589 73 63 00to the leak tester 124 589 15 21 00.

2 Fit cooling system pressure cap onto thedouble connection 000 589 73 63 00.

3 Test the opening pressure by pumping.

Testing vacuum valve

The vacuum valve (arrow) must be contactingthe rubber seal. It must be easily raised andmust spring back when released.

NoteAlways replace expansion tank caps which arecorroded (surface rust).

P20-0074-13

P50-2010-13

P20-2171.13

20.10 - 430/3

20440 n?sting CQQlant level indicator

Model 124

el e3pl p2e4 p3 e5 e 6 e7 812 ell 813 82 h2 e8 hl p6 Al

f a C b d s43 B5 s41 S42P16-0136-57

A l Instrument cluster B5 Oil pressure sensorel Left turn signal rndrcator s41 Coolant level Indicator lamp switch62 Right turn srgnal Indicator S42 Windshield washer level indicator lamp switche3 High beam rndrcator s43 Oil level Indicator lamp switche4 Fuel reserve warnrng lamp w 2 Ground, front right next to lamp unrte5 Battery charge rndrcator X27 Plug connector, starter harnesse6 Brake pad wear lndrcator lamp a Main ground behlnd Instrument cluster Wl87 Brake fluid and parkrng brake indicator lamp b Fuse 7 terminal 15e6 Instrument lighting C Fuse 5 terminal 15el 1 Coolant level lndrcator lamp d Lamp monitor unit812 011 level lndrcator lamp Preglow time relay terminal Lae13 Wtndshleld washer level lndrcator lamp814 Bulb failure Indicator lampe16 Preglow Indicator lamph l Wamrng buzzerPl Coolant temperature indicatorP2 Fuel gaugeP3 Oil pressure gauge~6 Electronic clock

Wiring diagram of engine oil level indicator, coolant level indicator, windshield washer level indicator

20.10 - 440/l

Model 126 1986


Alele2e3e4e5e6e7e8el 1e12e13e14e15e16hlh2PlP2P3P7

Instrument clusterLeft turn signal tndrcatorRight turn srgnal rndrcatorHigh beam rndrcatorFuel reserve warning lampBattery charge lndrcatorBrake pad wear rndtcator lampBrake fluid and parking brake tndrcator lampInstrument lightingCoolant level Indicator lamp011 level lndrcator lampWIndshield washer level rndtcator lampBulb failure rndlcator lampAlrbag indicator lamp (RSISRS)Preglow lndrcator lampWarning buzzerAudible turn signal rndlcatorCoolant temperature IndicatorFuel gaugeOil pressure gaugeElectronic clocktachometer

B5 011 pressure sensors41 Coolant level rndrcator lamp switchS42 Windshield washer level Indicator lamp switchs43 011 level lndrcator lamp swatchWl Main ground behind Instrument clusterw 2 Ground, front right next to lamp unitX27 Plug connector, starter harnessf Preglow time relay terminal La

20.10 - 44012

Model 126 1990

813 elle6 07 e5_--

p2e4 p3 812 ~163 r l ~8 e8-T-

h2 el e2 p7 e16 614 e15

-1

S42 s41 B5

Iir

Al

P18-0137.57


Alele2e3e4e5e6e7e8elle12e13e14e15e16h2PlP2P3P7~6Vl

Instrument clusterLeft turn signal lndrcatorRrght turn slgnal rndrcatorHigh beam IndicatorFuel reserve warning lampBattery charge IndicatorBrake pad wear lndlcator lampBrake flu/d and parkrng brake rndtcator lampInstrument lightingCoolant level tndrcator lamp011 level indicator lampWindshIeld washer level lndlcator lampBulb failure Indicator lampArrbag indicator lamp (RSISRS)Preglow indicator lampAudrble turn signal lndtcatorCoolant temperature indicatorFuel gaugeOil pressure gaugeElectronic clock/tachometerElectronic speedometerInstrument lrghtlng rheostat

I35 011 pressure sensorS10/2xl Connector, front right brake pad contact sensors41 Coolant level rndrcator lamp switchS42 WIndshIeld washer level rndrcator lamp switchs43 011 level lndlcator lamp switchWI Main ground behind Instrument clusterX27 Plug connector, starter harness

2010 - 44013

Model 201

e16 p7

---tT-r-

If )b )a !c td s41 S42Pl8-0138-57

Wiring diagram of engine oil level indicator, coolant level indicator, windshield washer level indicator(see Wiring Diagrams Volume 5 for further information)Al Instrument cluster BS 011 pressure sensor

el Left turn srgnal indtcator s41 Coolant level lndtcator lamp switche2 Right turn slgnal Indicator S42 Windshield washer level lndrcator lamp switche3 High beam Indicator s43 011 level lndrcator lamp switche4 Fuel reserve warning lamp Wl Main ground (behind Instrument cluster)e5 Battery charge indicator x5/2 Connector, interior/starter 4-pme6 Brake pad wear lndlcator lamp a Main ground behind Instrument cluster Wle7 Brake fluid and parking brake tndrcator lamp b Electrical centre, connector contact 15e8 Instrument lighting termrnal 15 unprotectede l l Coolant level Indicator lamp C Electrical centre, connector D contact 2e12 011 level Indicator lamp terminal 15 fuse 8e13 WIndshield washer level Indicator lamp d Electncal center, connector D contact 8 alternatore16 Preglow Indicator lamp terminal 6 1hl Warning buzzer f Preglow time relayh2 Audible turn signal IndicatorPl Coolant temperature lndlcatorP2 Fuel gaugeP3 Oil pressure gauge~6 Electronic clock

20.10 - 44014

Test data

Resistance at coolant level sensor with “max” coolant level @JQ

Resistance at coolant level sensor with “min” coolant level approx. 15 R

Battery voltage approx. 12 V

Commercial tool

Multimeter e. g. SUN,DMM-5

Complaints

A.

I%.

C.

Indicator lamp remains on when enginerunning and coolant level correct.

Indicator lamp does not light up whenkey in position “2”.

Indicator lamp does not light up whenengine running and coolant level below“min”.

Testing

A. Indicator lamp remains on when enginerunning and coolant level correct.

Test coolant level sensor. Detach connector.Connect both pins to multimeter and testresistance.

Readout: 00 Q

20.10 - 440/s

Check cable. Remove instrument cluster. Testcontact 12 of 15pin connector to ground withmultimeter.

Readout: 00 !A

I Replace gauge. I

I End of test _I

B. Indicator lamp does not light up whenkey in position “2”.

Check operation of bulb.

Remove instrument cluster. Measure voltageat contacts 6 and 9 of Spin connector withmultimeter.

Readout: approx. 12 V

Yes I No I

I Replace gauge. I

P2Q-0066-13

P20-0076-13

1I End of test I

2 0 . 1 0 - 440/6

6. Indicator lamp does not light up whenengine running and coolant level below“min”. Control function section ‘W inorder.

Check coolant level sensor. Detach connector.Connect both pins to multimeter and testresistance.

Readout: approx. 5 Q

Yes

Check cable. Connect multimeter to 2-pincoolant level sensor connector (brown cable)and battery positive.

Readout: approx. 12 V

Yes I No

Jumper coolant level sensor connector. Withkey in position “2”, indicator lamp should light

UP.

Yes I No

Rectify open circuit according to

P20-0077-13

-.

====I

-.

P 20 -0078 -13

20.10 - 440/7

20-445 Function of coolant level indicator

550 Coolant level sensor551 Float552 0-rmg

General

P20-0062-35

The coolant level indicator monitors the coolantlevel in the expansion tank when the engine isrunning.

The coolant level indicator lights up when theignition is switched on (control function) andgoes out as soon as the engine is running.

For the control function, the coolant levelindicator shows a weak light and a bright light ifthere is a fault during engine operation.

Componentsl Coolant level sensor (550) in expansion tankl Indicator lamp in instrument cluster.

Symbol: radiator.

20.10 - 445/l

To ensure that the coolant level sensor iscorrectly installed, it has two lugs of differentwidth which fit into matching slots on theexpansion tank (arrows).

The sensor is press-fitted in the expansion tankand sealed with an O-ring. Remove locking ringin order to withdraw the coolant level sensor.

Function

The coolant level in the expansion tank issensed by a float (551) with permanent magnetattached to the coolant level sensor.

Below a certain coolant level the contact isclosed and the indicator lamp lights up.

P20- 2128-13

Depending on driving style the indicator lamplights up briefly and later shows a steady light. Ifthe indicator lamp lights up, top off coolant.

2 0 . 1 0 - 44512

emoval and installation of overflow tank

614

Front right wheel . . . . . . . . . . . . . . . . . . . . . . . remove, refit.Tightening torque 110 Nm.

Partition panel (613) under front fender . . . . . . . . remove, install (step 2).

Vacuum reservoir (625) ................... remove, install (step 3).

Overflow tank (614) ..................... remove, install (step 4).

Special tool

001 589 66 21 0000

20.10 - 4501'1

Removal and installation

1 Remove right front wheel.

2 Unscrew bolts (623) and nuts (622), removepartition panel (6 13).

3 Detach vacuum hose (618). Remove bolts(629) and remove vacuum tank (625).

4 Remove bolts (619) and nut (621). Detachhose (615) and remove overflow tank (614).

5 Install in the reverse order.

20.10 - 450/2

70012 engine cooling system

Documents