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Check the compression pressure in the cylinders
|  | To perform the verification procedures of the compression pressure will need assistance assistant. |
- Compression gives an idea about the state of the engine. The test results show, by way of valves and whether the pistons (piston ring), or whether they are worn. In addition, test results permit to decide whether to replace the engine, whether it is sufficient or complete renovation to replace the cylinder head gasket. To verify the required compressometer that for petrol engines available in specialty stores at an affordable price.
| For diesel engines Compression needs to limit measurements to about 40 bar. |
- Warm up the engine to normal operating temperature (80 ?� C), make sure of the completeness of the battery charge.
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Petrol models | - Stop the engine and, in accordance with a joint, remove the cover of the power unit, air cleaner assembly, and - with the appropriate equipment, - a resonator chamber with a connecting sleeve (see chap. Power supply system and exhaust).
- Remove the spark plug and turn the engine a starter.
- Fill packing compression tester to the spark plug hole of the first cylinder.
- Depress the accelerator pedal and the engine cranking the starter, consider the meter (need the help of an assistant) - the result of the measurement record.
- Operating in a similar manner, to measure alternately the remaining compression pressure in the engine cylinders.
- Stop the engine, remove the compression gauge, screw the spark plug and replace all filmed for access components.
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Diesel models Turn off the engine and remove the air distribution sleeves tract pressurization system and cover the cylinder head cover. Checking compression pressures on diesel models equipped with engine series 612 Checking compression pressures on diesel models equipped with engine series 628 M612 | - Remove the spark plugs.
- With threaded attachment with a flexible connection hose to connect compressometer spark plug hole of the first cylinder.
- Proceed in a manner similar to that described above for gasoline engines.
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M628 Checking compression pressures on diesel models equipped with engine series 628
| - Remove the air cleaner assembly.
- Disconnect the air distribution pipe inlet air path.
- Disconnect the connector valve, pressure regulator
- Remove the spark plugs.
- Proceed according to the instructions for petrol engines.
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All models | - Compare the results of the measurement requirements of Specifications.
- Maximum permissible differential pressure in the individual cylinders can be 1.5 bar (for diesel engines 3.0 bar).
- Compression in the serviceable engine is growing very fast. Low value shown after the first cycle, increases with subsequent cycles indicates the wear of piston rings. Low value after the first cycle does not increase after the next, indicating that any leaking valves or broken head gasket (the reason could also be a crack in the head). To decrease the compression may result in the presence of carbon on the valve plates.
- It should be borne in mind that because of the different speed starter for different models obtained from measurement results may vary. The results obtained in the measurement of compression should be approximately the same for all cylinders.
- If the pressure in any cylinder is at the minimum allowed, and even below, to determine the cause, follow these steps. Pour into the cylinder through the spark plug hole teaspoon of motor oil and repeat the measurement of compression.
- If the addition of oil temporarily improved compression, the cause of its decline, most likely, is the wear of the piston rings or cylinder. If you increase the compression has occurred, it can be assumed that the reason - valve or a leak in a broken head gasket.
- Low compression in two next cylinders almost certainly - a consequence of the breakdown of head gaskets. The presence of coolant in the combustion chamber or in the crankcase will confirm this assumption.
- If the compression in a cylinder about 20% lower than in the other, besides the idle speed is unstable, the reason may be excessive wear of the cam camshaft.
- Once validated, replace the spark plug (see Chapter Current leaving and service), put them tips of high-voltage wires, attach the connector to the ignition coil. Replace the plastic cover of the engine and the fuel pump fuse.
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Check cylinder for leaks | - During this test determines the rate of release of the cylinders are injected into the compressed air directly leaks. This test is an alternative to compression check. Moreover, from many points of view, it is much more effective as visually identify the source of the leak is easier to comprehend than the results of the measurement of compression.
- Equipment required to check for leaks, does not apply to public, so perform this test is necessary to entrust the Service Centre.
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