Mercedes W163
+ Mercedes-Benz Cars of a class M (W163)
+ Governing bodies and receptions of safe operation
+ Current leaving and service
- Engine
Check of kompressionny pressure in cylinders
Engine check by means of the vacuum gage
Replacement of a belt of a drive of auxiliary units and elements of the mechanism of its tension
+ Petrol models
+ Diesel models
+ Systems of cooling, heating and air conditioner
+ the Power supply system and production of the fulfilled gases
+ Systems of electric equipment of the engine
+ Manual box of gear shifting
+ Avtomaticheckaya transmission
+ Transmission line
+ Brake and auxiliary systems
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
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Check of kompressionny pressure in cylinders
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For performance of procedure of check of kompressionny pressure the help of the assistant is required. |
- The compression provides guidance on an engine condition. Results of check show, whether as it should be valves and pistons (piston rings), or they are worn-out. Whether Besides, results of check allow to make the decision to replace the engine, whether the complete repair is required to it or to replace sealing laying of a head of cylinders enough. For check it is required компрессометр which for petrol engines is offered in specialized shops for reasonable price.
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For diesel engines it is necessary компрессометр with a limit of measurements approximately to the 40th bar. |
- Warm up the engine to normal working temperature (about 80°С), make sure of completeness of a charge of the storage battery.
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Petrol models
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- Muffle the engine and, according to a complete set, uncover the power unit, assembly of an air purifier and, - at the corresponding complete set, - the rezonatorny chamber with a connecting sleeve (see. Head of the Power supply system and production of the fulfilled gases).
- Turn out spark plugs and turn the engine a starter.
- Fill a nozzle компрессометра in a candle opening of the first cylinder.
- Squeeze out a pedal of gas and, turning the engine a starter, consider measuring instrument indications (the help of the assistant is required), - result of measurement write down.
- Operating in a similar manner, serially measure kompressionny pressure in the remained cylinders of the engine.
- Muffle the engine, disconnect компрессометр, screw spark plugs and establish into place all components acting in film for the purpose of ensuring access.
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Diesel models Muffle the engine and uncover an airdistributing sleeve of a path of system of pressurization and an overlay of a cover of a head of cylinders.
Check of kompressionny pressure on the diesel models equipped with the engine of a series 612
Check of kompressionny pressure on the diesel models equipped with the engine of a series 628
М612
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- Turn out glow plugs.
- By means of a carving nozzle with a flexible connecting hose connect компрессометр to a candle opening of the first cylinder.
- Further act as it should be, similar described above for petrol engines.
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М628
Check of kompressionny pressure on the diesel models equipped with the engine of a series 628
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- Remove air purifier assembly.
- Disconnect an airdistributing branch pipe of an inlet air path.
- Disunite the socket of the valve regulator of pressure
- Turn out glow plugs.
- Further act according to the instructions provided for petrol engines.
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All models
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- Compare results of measurement by requirements of Specifications.
- The most admissible difference of pressure in separate cylinders can make 1.5 bar (for diesel engines 3.0 a bar).
- 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.
- 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.
- 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.
- 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.
- 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.
- 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 cam-shaft.
- After completion of check establish to the place of a spark plug (address to Head the Current leaving and service), put on them tips of high-voltage wires, attach the socket to the ignition coil. Establish into place a plastic cover of the engine and a safety lock of the fuel pump.
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Check of cylinders on leaks
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- 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.
- The equipment necessary for check on leaks, does not belong to public therefore performance of this check should be entrusted specialists of the service center.
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