Mercedes-Benz G-class (W463) since 1999 of release
1. Introduction
2. Governing bodies and operation receptions
3. Current leaving and service
4. Engine
4.1. Check of kompressionny pressure, assessment of a condition of cylinders
4.2. Engine check by means of the vacuum gage
4.3. Replacement of a belt of a drive of auxiliary units and elements of the mechanism of its tension
4.4. Check of pressure of impellent oil
4.5. Calculation of a consumption of oil
4.6. Check and adjustment of base provision of camshafts
4.7. Verification of the base provision of a balancing shaft (only M112 engines and 628)
4.8. Check of a condition of a chain of a drive of GRM on the M628 engine
4.9. Check of correctness of installation of a corner of an advancing of ignition on petrol models
4.10. Removal and installation of the power unit
4.11. Removal and installation of support of a suspension bracket of the power unit
5. Systems of cooling, heating, ventilation and air conditioning
6. A power supply system and production of the fulfilled gases
7. Systems of electric equipment of the engine
8. Automatic transmission
9. Transmission line
10. Brake and auxiliary systems
11. Suspension bracket and steering
12. Body
13. Onboard electric equipment
14. Schemes of electric connections


 







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4.1. Check of kompressionny pressure, assessment of a condition of cylinders

Check of kompressionny pressure

For performance of procedure of check of kompressionny pressure the help of the assistant is required.

Measurement of kompressionny pressure allows to make general idea about current state of such internal components of the engine, as laying of heads of cylinders, elements of the klapanny mechanism, pistons and piston rings. The analysis of results of check allows to define, whether the engine needs major regenerative maintenance, or it is rather simple to replace sealing laying of a head. Measurement is made with the help компрессометра.

For diesel engines it is necessary компрессометр with a limit of measurements approximately to 40 atm.

Warm up the engine to normal working temperature (about 80°С), make sure of completeness of a charge of the storage battery.

Petrol models

For measurement of kompressionny pressure it is necessary to use the equipped remote switch of a starter a measuring instrument (it is shown on model 202 example)

01 — Kompressometr
02 — the Remote switch of a starter

8 — the ignition Switch

 PERFORMANCE ORDER

  1. Muffle the engine and, according to a complete set, remove air purifier assembly (see. Head of the Power supply system and production of the fulfilled gases).
  2. Serially turn out spark plugs (see. Head of System of electric equipment of the engine).
  3. Take a key from the electronic switch of ignition (EIS).
  4. Prepare equipped with the remote switch of a starter компрессометр
  1. Uncover (1) assembly block of the module of management
  1. Connect a clip (And) a measuring instrument to the X12/3 plug
  1. Disunite the X35/63 socket and connect to it the adapterny wire (2) equipped with the 6-contact tip, - the second end of a wire connect to a wire компрессометра

At measurement of a compression it is not necessary to turn a starter from the ignition switch!

  1. Densely press a measuring instrument nozzle to a bottom of a candle niche of the first cylinder.
  1. Completely open a butterfly valve and, turning the engine a starter activated from the button of the remote switch компрессометра, consider indications of the last. Result of measurement write down.

For removal of a deposit from walls of cylinders the engine should be turned within about 5 seconds.

  1. Operating in a similar manner, serially measure kompressionny pressure in the remained cylinders of the engine.
  2. Muffle the engine, disconnect компрессометр, screw spark plugs and establish into place an air purifier.

Diesel models

Check of kompressionny pressure on the diesel models equipped with the engine of a series 612

1 — an air distributor Cover
2 — the Overlay of a cover of a head of cylinders
3 — Kompressometr

4 — the Connecting hose
5 — the Carving nozzle
R9 — the Glow plug

Check of kompressionny pressure on the diesel models equipped with the engine of a series 628

3 — Kompressometr
5 — the Carving nozzle
6 — air purifier Assembly
7 — the Contact socket

R9 — the Glow plug
Y74 — the pressure Valve regulator

 PERFORMANCE ORDER

  1. Muffle the engine and uncover the air distributor of a sleeve of a path and an overlay of a cover of a head air purifier cylinders/assembly (see. Head of the Power supply system and production of the fulfilled gases). Turn an "ignition" key in situation 0.

М612

For measurement of kompressionny pressure it is necessary to use the equipped remote switch of a starter a measuring instrument (it is shown on model 202 example)

01 — Kompressometr
02 — the Remote switch of a starter

8 — the ignitions Switch
Y74 — the pressure Valve regulator


 PERFORMANCE ORDER

  1. Turn out glow plugs (see. Head of System of electric equipment of the engine).
  2. Prepare equipped with the remote switch of a starter компрессометр.
  1. Uncover (1) blocks of external start (2) and connect a measuring instrument clip to the X4/30 plug
  1. Uncover (arrow) on the right under the dashboard
  1. Take from the assembly block of the relay (3) starters which point of installation is noted by S letter
  1. To a block (4) relays (S letter on a payment of the assembly block) connect an adapterny wire компрессометра

At measurement of a compression it is not necessary to turn a starter from the ignitions switch!

  1. By means of a carving nozzle with a flexible connecting hose connect компрессометр to a candle opening of the first cylinder (see an illustration Check of kompressionny pressure on the diesel models equipped with the engine of a series 612).
  2. Further act according to the instructions provided for petrol engines, - need for pedal squeezing gas/opening of a butterfly valve is absent.

For measurement performance the engine should be turned not less than eight times.


М628

 PERFORMANCE ORDER

  1. Disunite the socket of the valve regulator of pressure (see an illustration Check of kompressionny pressure on the diesel models equipped with the engine of a series 628) and turn out glow plugs (see. Head of System of electric equipment of the engine).
  2. Prepare equipped with the remote switch of a starter компрессометр (see an illustration Check of kompressionny pressure on the diesel models equipped with the engine of a series 628) and, operating further according to instructions (on an example of models 220.028/128 equipped with engines 629.960), connect it to plugs of the corresponding safety lock in the right forward assembly block.
  1. Uncover the right forward assembly block of safety locks and the relay (K40/7) and take from the nest maxi safety lock (60А) the fan of system of cooling of the engine, then disunite the white socket (1)
  1. Connect adapterny wires компрессометра to the base plug (30) of a landing nest of a safety lock (33) and the plug (50) of the white socket (1)

At measurement of a compression it is not necessary to turn a starter from the ignitions switch!

  1. By means of a carving nozzle with a flexible connecting hose connect компрессометр to a candle opening of the first cylinder (see an illustration Check of kompressionny pressure on the diesel models equipped with the engine of a series 628).
  2. Further act according to the instructions provided for petrol engines, - need for pedal squeezing gas/opening of a butterfly valve is absent.

For measurement performance the engine should be turned not less than eight times.

  1. Alternatively measurement of kompressionny pressure can be made by means of the diagnostic STAR DIAGNOSIS input reader, - act according to instructions enclosed to the device.

All models

 PERFORMANCE ORDER

  1. Compare results of measurement by requirements of Specifications.
  2. The most admissible difference of pressure in separate cylinders can make 1.5 atm (for petrol engines) and 3.0 atm (for diesel engines).
  3. The compression grows in the serviceable engine very quickly. The low value shown after the first cycle, increasing with the subsequent cycles, indicates wear of piston rings. Low value after the first cycle, not increasing after the following, signals that or valves are not tight, or laying of a head of the block (the crack in a head can be the reason also) is punched. To decrease in a compression can lead deposit existence on plates of valves.
  4. It is necessary to mean that because of different speed of rotation of a starter on different models the results received as a result of measurements can differ. The results received at measurement of a compression, should be approximately identical to all cylinders.
  5. If pressure is in any cylinder at level minimum admissible and even below, for clarification of the reason execute the following actions. Pour in in the cylinder through an opening for a candle a teaspoon of impellent oil and repeat compression measurement.
  6. If oil addition temporarily improved a compression, the reason of its decrease, most likely, is wear of the piston, rings or the cylinder. If the increase in a compression did not occur, it is possible to assume that the reason - in a leakage of valves or the punched laying of a head of the block.
  7. Low compression in two next cylinders almost for certain - a consequence of breakdown of laying of a head. Availability of cooling liquid in chambers of combustion or in a case of the engine will confirm this assumption.
  8. If the compression in one of cylinders approximately for 20 % is lower, than in the others, besides turns of idling are unstable, the reason, probably, excessive wear of a cam of a camshaft.
  9. After completion of check establish to the place of a candle, connect to them electroconducting, on petrol engines restore initial connection of the coil (ек) ignitions. Establish into place a plastic cover of the engine and a safety lock of the fuel pump.

Check of cylinders on leaks

During this check are defined speed of an exit from cylinders of the compressed air pumped in them and directly a place of leaks. This check is alternative to compression check. Moreover, from many points of view it is much more effective as visually to reveal a source of leak simpler, than to comprehend results of measurement of a compression.

All models

 PERFORMANCE ORDER

  1. Warm up the engine to normal working temperature (80°С), then muffle it.

Petrol models

Check of cylinders of petrol engines on leaks


 PERFORMANCE ORDER

  1. Accurately turn the cover equipped with the built in latch (2) broad tanks (1) system of cooling to the first emphasis, wait pressure dumping, then unscrew a cover finally.
  2. Turn out spark plugs (19).
  3. Turning the engine for the central bolt of a cranked shaft in the normal direction, bring the piston of the cylinder subject to check into the provision VMT of the end of a step of compression, then connect to the corresponding candle opening a special tester (04), previously having made its calibration, - act in strict accordance with instructions enclosed to the device.
  4. Uncover a jellied mouth of impellent oil (3).
  5. Submit to the cylinder the compressed air and according to indications of a measuring instrument estimate speed of dumping of pressure. Result write down.

If during check the cranked shaft starts to be turned, block it by means of the special adaptation (see. Sections Check and adjustment of base provision of camshafts and Verification of the base provision of a balancing shaft (only M112 engines and 628)).

  1. Repeat check for the remained cylinders, - act as ignition (see. Head of System of electric equipment of the engine).
  2. Disconnect a measuring instrument and screw to the place of a spark plug.

Diesel models

Check of cylinders of diesel engines on leaks

 PERFORMANCE ORDER

  1. Turn a cover (1) broad tank (2) systems of cooling counter-clockwise on a half of turn, wait pressure dumping, then uncover finally.
  2. Remove panels of furnish of the engine (М612) / assembly of an air purifier (М628).
  3. Turn out glow plugs (R9).
  4. On the models equipped with the engine of a series 628, remove a cooler of air of pressurization (see. Head of the Power supply system and production of the fulfilled gases).
  5. On the models equipped with the engine of a series 612, remove the vyazkostny coupling of the fan of system of cooling (see. Head of System of cooling, heating, ventilation and air conditioning).
  6. Turning the engine for the central bolt of a cranked shaft in the normal direction, bring the piston of the cylinder subject to check into the provision VMT of the end of a step of compression, then connect to the corresponding candle opening a special tester (04), previously having made its calibration, - act in strict accordance with instructions enclosed to the device.
  7. Further affect in the manner similar described above for petrol engines (see paragraphs with 4 on 7 points Check of cylinders leaks - petrol models).

All models

 PERFORMANCE ORDER

  1. Compare results of check with requirements of Specifications. In case of need make necessary regenerative repair.

Check of cylinders by means of a lamp sampler

Petrol models

Check of cylinders of petrol engines by means of a lamp sampler


 PERFORMANCE ORDER

  1. Turn out spark plugs.
  2. Turning the engine in the normal direction for the central bolt of a cranked shaft, bring the subject piston to cylinder check into situation NMT.
  3. Operating strictly according to instructions of manufacturers, connect a special lamp sampler (05), fill its flexible light guide in the corresponding candle opening and make a visual assessment of a condition of walls of the cylinder which should have an opaque shade without traces of a honingovochny notch.
  4. Operating in a similar manner, examine walls of the remained cylinders (as ignition).
  5. In case of need remove the engine, heads of cylinders and make more detailed direct survey of mirrors of cylinders and necessary regenerative repair.

Diesel models

 PERFORMANCE ORDER

  1. Take from the lock an "ignition" key.
  2. Remove panels of furnish of a head of cylinders (М612) / assembly of an air purifier (М628).
  3. Turn out glow plugs (R9).
  4. Remove nozzles (Y76) (see. Head of the Power supply system and production of the fulfilled gases).
  5. On the models equipped with the engine of a series 628, remove a cooler of air of pressurization (see. Head of the Power supply system and production of the fulfilled gases).
  6. On the models equipped with the engine of a series 612, remove the vyazkostny coupling of the fan of system of cooling (see. Head of System of cooling, heating, ventilation and air conditioning).
  7. rovorachivy the engine for the central bolt of a cranked shaft in the normal direction, bring the subject piston to cylinder check into situation NMT.
  8. Further act in the manner similar described above for petrol engines (see paragraphs with 3 on 5).


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4.2. Engine check by means of the vacuum gage