Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car



Mercedes S-Class
+ Mercedes-Benz cars of the class S (W-140)
+ Operation manual
- Routine maintenance
   Specifications
   Active system of the warning of the term of approach planned THAT (ASSYST)
   Schedule of routine maintenance
   General information on control
   Check of levels of liquids, control of leaks
   Check of a condition of tires and pressure in them, designation of tires and disks of wheels, rotation of wheels
   Replacement of motive oil and oil filter
   Check of the brake system
   Check of fuel system, replacement of the fuel filter
   Check of a state and replacement of hoses of a motive compartment, localization of leaks
   Check of a condition of ridge belts of the streaming drive of auxiliary units
   Check of functioning of the cooling system and frost resistance of cooling liquid, liquid replacement
   Check of a condition of system of production of the fulfilled gases
   Check of the ATF level, replacement of the AT filter
   Visual check of tightness of automatic transmission
   Check of a condition of components of a suspension bracket and steering
   Check of a condition of protective covers of power shafts
   Check of the air conditioning system
   Lubricant of limiters of doors and cylinders of locks
   Visual control of a seat belt and block of a safety cushion
   Check of operability of headlights and horn
   Check of a state, adjustment and replacement of brushes of screen wipers
   Check of a condition of the battery, care of it and charging
   Replacement of the saloon filter
   Replacement of brake fluid
   Check and replacement of spark plugs, check of a condition of high-voltage wires (petrol models)
+ Engine
+ Cooling systems, heating
+ Power supply system and release
+ Engine electric equipment
+ Gear shifting box
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment






Check of levels of liquids, control of leaks

Below the procedures of check of level of liquid made through each 400 km of a run or weekly are described. The description of other checks of levels of liquid can be found further in the Sections devoted to specific procedures of service. Irrespective of check intervals according to the schedule do not assume that liquid followed under the car, - similar leaks indicate malfunction which should be eliminated immediately.

When checking level of any working liquid the car has to settle down strictly horizontally!


Liquids are the integral component of lubrication systems, coolings, brake and systems of washing of a windshield. In view of a gradual consumption and/or pollution of liquids in the course of normal operation of the car, they should be replaced periodically. Before starting a liquid dolivaniye in any of the listed components study requirements of Specifications to types and volumes of the applied liquids.

Motive oil

Visual control of leaks

At the greasy engine and a big consumption of oil check places of the most probable development of leaks:
  • Sealing element of a cover of a jellied mouth, - check for existence on existence of cracks and other mechanical damages;
  • Components of system of ventilation of a case (in particular - the ventilating hose going from a cover of a head of cylinders to an air absorption hose);
  • Laying of a cover of a head of cylinders;
  • Laying of a head of cylinders;
  • Sealing ring of a drain stopper of the pallet of a case of the engine;
  • Laying of an oil filter, - attentively study the place of a prileganiye of the filter to a flange;
  • Laying of the pallet of a case.
  • Forward and back epiploons of a bent shaft.
  • Wrap the generator in polyethylene, spray the engine a usual cold cleaner, - then, through short time, - wash out water on car wash.

    Powder joints of the interfaced surfaces and sealing elements of the power unit outside with lime or talc.

    Check oil level, if necessary add.

    During short (about 30 km) trips (it is desirable on the high-speed route) warm up the engine, - the warmed oil differs in the increased fluidity and easier filters through thinnesses.

    Park the car and, highlighting themselves a lamp, investigate the engine for the purpose of localization of sources of leak of oil.

    Remove the causes of development of leaks.

    Check of level

    The maximum admissible consumption of motive oil makes 1l/1000 km, real level of consumption of oil depends on a manner, - the frequent movement with high turns of the engine leads to increase in a consumption of oil.

    Information on the principle of functioning of a control lamp of level of motive oil is provided in the Section Combination of Devices, measuring instruments and control lamps and light indicators of the Head Operation manualof


    The control lamp which is built in assembly of the lock of ignition warns about dangerous falling of level of motive oil of the driver (see the Section Combination of Devices, measuring instruments and control lamps and light indicators of the Head the Operation manual). The sensor switch of level of oil is located under the car, in the right forward corner of the pallet of a case of the engine.


    Location of a jellied mouth and the probe of measurement of level of motive oil on the S280 and S320 models

    1 — the Probe


    Location of a jellied mouth and the probe of measurement of level of motive oil on the S300TDI models


    1 — Gorlovina
    2 — the Probe


    Location of a jellied mouth and the probe of measurement of level of motive oil on the S420 and S500 models

    1 — the Probe
    2 — Gorlovina


    Location of a jellied mouth and the probe of measurement of level of motive oil on the S600 models

    1 — the Probe
    2 — Gorlovina


    Check of level of motive oil is made by means of the measuring probe passed throughout the directing tube and the pallet of its case lowered in the engine to the lower point. Check of level of oil has to be made before the first in the present day trip, or about 5 minutes later after an engine stop. If to execute check immediately after switching off of the engine, its results will adequately not reflect a situation as a part of oil will be distributed on internal galleries and components of the engine.

    Take the measuring probe from the directing tube and dry wipe its edge with pure rags or a paper towel. Fill the probe back in a tube against the stop, then again take. Having examined a probe edge, estimate the size of the site moistened with oil. Level of oil has to be between the top and lower marks in a probe edge. In case of need add the corresponding amount of oil of the required grade in the engine.


    Lowering of level out of limits of the lower bound of admissible range leads to development of oil starvation of the engine fraught with serious mechanical damages of the last. Try not to pour also oil above the top mark as it can lead to a pelting of spark plugs or failure of epiploons of the power unit as a result of excessive increase in pressure.

    To fill in oil in the engine it is necessary to uncover equipped with a carving of a jellied mouth. In order to avoid spraying of oil during its gas station in the engine use a funnel, or a butterdish with a long nose. Having filled in oil, screw and strongly tighten a cover of a jellied mouth, then start the engine and attentively examine a drain stopper and the surface of an oil filter interfaced to the block on existence of signs of leaks.

    Kill the engine, wait 5-10 minutes during which oil will merge in the pallet, then double-check its level.

    Surplus oil needs to be merged or pumped out, - the excessive level of motive oil can be the reason of failure of the catalytic converter. Track reliability of tightening of a cover of a jellied mouth.


    Check of level of engine oil is the important preventive procedure of service of the engine. Continuous decrease in level demonstrates existence of leak of oil as a result of failure of epiploons, damage of sealing laying, wear of piston rings or the directing plugs of valves. If oil on color or a consistence reminds milk, or at it there are water drops, it speaks about possible damage of laying of a head of cylinders, or formation of cracks to a body of a head(s) or the block. Check has to be made immediately. During measurement of level of oil always check also its state. Big and index fingers remove oil traces from a probe edge, - in case of presence at it of small metal particles oil is subject to replacement (see the Section Replacement of Motive Oil and Oil Filter).

    Cooling liquid of the engine

    Do not allow hit of antifreeze on open parts of the body and the painted surfaces of the car.

    Immediately wash away casual splashes a plentiful amount of water.

    Remember that antifreeze is extremely toxic liquid and its hit in an organism even in small amounts is fraught with the most serious consequences, up to a lethal outcome.

    Never leave antifreeze stored in leaky closed container, immediately collect the cooling liquid spilled on a floor.

    Remember that the sweetish smell of antifreeze can draw to itself attention of children and animals.

    About ways utilization of the fulfilled cooling liquid consult with local authorities, - in many regions of the world special points on different reception of working off are equipped.

    Do not merge old cooling liquid in the sewerage and on the earth at all!

    Recently nontoxical grades of antifreeze are developed, nevertheless, they also had to be utilized in an organized order



    All cars considered in this manual are equipped with the cooling system of compensation type working with an excessive pressure. The white plastic broad tank is located in a motive compartment and connected by a hose to a radiator.

    In process of an engine warming up in the course of its work the extending cooling liquid fills a tank. When cooling the engine cooling liquid automatically comes back to the cooling system that provides maintenance of constant value of its level. The control lamp included in structure of a combination of devices warns about dangerous falling of level of cooling liquid of the driver (see the Section Combination of Devices, measuring instruments and control lamps and light indicators of the Head the Operation manual). The sensor switch of level of cooling liquid is located in the lower part of a broad tank of the cooling system.


    Check of level of cooling liquid in the tank has to be made regularly, at strictly horizontal position of the car and the switched-off engine. In a cold condition of cooling liquid its level has to reach the mark "MIN" in a broad tank. In a hot condition of cooling liquid level has to be about 1.5 cm higher. In case of need make the corresponding adjustment, - add 40%/60% mix of antifreeze on the basis of ethylene glycol with water (see Specifications).

    Banish the car and again measure the level of cooling liquid. If to the necessary level it is required to add only a small amount of cooling liquid, then for this purpose it is possible to use clear water. However frequent additions of water will dilute antifreeze. To provide a normal ratio of antifreeze and water, always add to the necessary level the required mix.

    If the level of cooling liquid falls regularly, then in system leak existence is possible. Examine a radiator, hoses, a cover of a jellied mouth, drain traffic jams and the water pump (address the Section Check of Functioning of the Cooling System and Frost Resistance of Cooling Liquid, liquid replacement). If leaks are not revealed, make check of tightness of a cover of a broad tank and a radiator in conditions HUNDRED.

    If you need to uncover, wait until the engine completely cools down, then wrap up a piece of thick rags around a cover and turn off it to the first emphasis. If at the same time from under a cover steam or cooling liquid begins to escape, let's the engine cool down a little more, and only then uncover.

    It is necessary to check a condition of cooling liquid also. It has to be rather pure. If liquid has brown or rusty color, it is necessary to merge, wash out it system and to fill it with new mix. Even if cooling liquid looks normally, the corrosion inhibitors which are its part lose over time the efficiency therefore it should be replaced through certain periods.

    For check of frost resistance of cooling liquid it is necessary to use the areometer.

    Brake fluid

    Brake fluid can do harm to your eyes and damage the painted surfaces of the car therefore be extremely careful at the treatment of her. Do not use brake fluid which long time stood open, or which there are more than one year. Brake fluid has property to absorb moisture from air that can lead to dangerous loss of efficiency of the brake system. Use only the recommended type of brake fluid. Mixing of various types of liquid can lead to failure of the brake system.


    The main cylinder of the brake system is installed in a back left corner of a motive compartment. Prevents operation of the control lamp which is built in a combination of devices about falling of level of brake fluid of the driver (see the Section Combination of Devices, measuring instruments and control lamps and light indicators in the Head the Operation manual) which float-operated sensor switch is built in a GTTs tank cover.

    Level of brake fluid is checked visually, on tags on the plastic tank installed on the main cylinder. Level of liquid has to be between tags of "MAX" and "MIN". If level is lower admissible, at first wipe top of the tank and a cover with pure rags to prevent hit of dirt in system after removal of a cover. Add to the necessary level the recommended liquid, but do not pour.

    Until the tank is uncovered, check liquid and the tank of the main cylinder for existence of pollution. If at it there are particles of a rust, dirt or a drop of water, liquid from system should be merged and filled in new.

    After addition of the tank to the necessary level make sure that the cover is established exactly, in order to avoid leak of liquid and/or hit of dirt.

    Liquid level in the main cylinder will fall slightly as a result of wear of frictional overlays of brake shoes. There is no need to add it until level remains near a tag of "MIN"; it will rise after replacement of slips. Very low level can indicate wear of brake shoes. Check them for wear existence (see the Section Check of the Brake System).

    If the level of brake fluid constantly falls, immediately check all system for existence of leaks. Survey brake lines, hoses and nipple connections, together with supports, wheel cylinders and the main cylinder (address the Sections Check of the Brake System, Check of a State and Replacement of Hoses of a Motive Compartment, localization of leaks).

    If when checking level of liquid the tank is empty or almost empty, the brake system has to be checked for existence of leaks and is pumped over (address Heads Coupling and the Brake system).

    Liquid of system of hydrostrengthening of a wheel (GUR)

    If liquid level in the tank fell below a zone, the corresponding temperature of liquid, steering with the hydraulic amplifier of the steering mechanism needs to be checked in a specialized workshop as liquid loss takes place. In this case it is not enough to be limited only to addition of level of liquid.


    Check of level of GUR liquid on the models equipped with engines of a series 104 and 119

    30 — the GUR Tank
    30s — the Plastic index


    Check of level of GUR liquid is made at a temperature about 20 °C. Level of liquid has to be between the marks "MIN" and "MOVE" of the plastic index of the tank / (except the models equipped with series 120 engines) / edges of the tank of the measuring probe which is built in in a cover (models with series 120 engines). The full volume of the tank makes 1.4 l.

    Information on adjustment of level of GUR liquid for diesel models at the time of drawing up the present manual by producers was not provided, the principle is similar to one of described above for petrol engines.

    Liquid of a washer of wind glass / lenses of headlights

    Easily we ignite a concentrate of stekloomyvayushchy means! At the address with a concentrate of stekloomyvayushchy means use of fire opened a flame and smoking are forbidden.


    Liquid for washing of a windshield contains in the plastic tank in the right forward corner of a motive compartment. The jellied mouth of the tank is removed in the panel of a front and is between the right block headlight and a radiator. Capacity of the tank is specified in Specifications.


    Prevents operation of the control lamp which is built in a combination of devices about falling of level of cooling liquid of the driver (see the Section Combination of Devices, measuring instruments and control lamps and light indicators of the Head the Operation manual). The sensor switch of a control lamp is built in in the top part of the tank of cooling liquid.


    In areas with a temperate climate the system can be filled with usual water, but it is recommended to add to means water for washing of glasses (the summer concentrate of MV has marking of S). The tank has to be filled no more than on two thirds that there was a free space on a case of expansion of water when freezing. In areas with cold climatic conditions it is necessary to use the special concentrate for washing of a windshield (marking of W) reducing a liquid freezing point which can be got in any shop of automobile accessories. Usually it is on sale in the concentrated or ready look. If you bought the concentrated antifreeze, mix it with water according to the instruction of the producer on packing.

    Do not use cooling system antifreeze - it will damage the painted surfaces of the car!