Testing all cylinders for leak down

NOTE: RISK OF DAMAGE
Damage to the engine .
If the engine is manually rotated in the wrong direction of rotation, the engine can be damaged .

Only rotate the engine manually in the correct direction of rotation: a) clockwise when looking at the damper, or b) counterclockwise when looking at the chain drive, b) applies only if the timing chain is installed in the rear.

NOTE: TECHNICAL INFORMATION
Before the leak down of the cylinders is checked, the special tool 2 302 630 must be adjusted or calibrated.

NOTE: TECHNICAL INFORMATION
The OT finder from the special tool 2 302 630 absolutely must be vertical, otherwise the measurement result can be falsified.

NOTE: The description is provided only at one cylinder. The procedure is the same for all other cylinders.

Preliminary work

Refer to REMOVING THE ACOUSTIC COVER .
Refer to RELEASING THE SERVICE OPENING IN SOUND INSULATION ON TOP OF ENGINE .
Refer to REMOVING ALL IGNITION COILS .
Refer to REMOVING ALL SPARK PLUGS .
Refer to REMOVING THE FRONT HOOD SEAL .
Refer to REMOVING THE COVER FOR THE CENTER ENGINE COMPARTMENT .
Refer to REMOVING UPPER CROSS CONNECTION .
Refer to REMOVING THE REAR TOP CROSS CONNECTION .
Refer to REMOVING THE FAN COWL .

Special tool 2 302 630

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NOTE: RISK OF DAMAGE
Damage to the engine .
If the engine is manually rotated in the wrong direction of rotation, the engine can be damaged .

Only rotate the engine manually in the correct direction of rotation: a) clockwise when looking at the damper, or b) counterclockwise when looking at the chain drive, b) applies only if the timing chain is installed in the rear.

NOTE: TECHNICAL INFORMATION
Before the leak down of the cylinders is checked, the special tool 2 302 630 must be adjusted or calibrated.

NOTE: The description is provided only at one component. The procedure is the same for all other components.

Keep set of special tools 2 302 630 at hand:

Number	Description
1	Pressure gauge
2	TDC Finder
3	Adapter for the spark plug thread (60)
4	Adapter for the spark plug thread

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Have the special tool 0 493 380 (11 6 480) 2 468 560 ready.

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Have the adapter for the spark plug thread (60) (1) ready.

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Screw in the adapter for the spark plug thread (60) (1) into the spark plug thread by hand.

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Tighten the adapter for the spark plug thread (60) (1) with a standard tool (2).

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Connect the TDC finder (1) to the adapter for the spark plug thread (60) (2).
The TDC finder (1) must engage audibly.

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NOTE: TECHNICAL INFORMATION
The OT finder from the special tool 2 302 630 absolutely must be vertical, otherwise the measurement result can be falsified.
Fit special tool 0 493 380 (11 6 480) .
Turn the engine by hand with the special tool 0 493 380 (11 6 480) .
If the piston goes upwards, the bubble level (2) in the cylinder tube (1) also goes upward in the arrow direction.
Turn the piston to TDC.
At TDC, both the piston and bubble level (2) are at the highest point in the cylinder tube (1).

» Valves are closed.

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NOTE: TECHNICAL INFORMATION
Before the leak down of the cylinders is checked, the special tool 2 302 630 must be adjusted or calibrated.
Connect the quick-release coupling (1) to the valve block (2) of the pressure gauge in the arrow direction.
The quick-release coupling (1) must engage audibly.

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Connect the compressed air hose (1) to the valve block (2) of the pressure gauge in the arrow direction.
The compressed air hose (1) must engage audibly.

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Unlock the pressure control valve (1) in the arrow direction.

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Turn the pressure control valve (1) in the arrow direction until the needle (2) of the pressure gauge is at 22%.

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Lock the pressure control valve (1) in the arrow direction.
The pressure control valve (1) must engage audibly.

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Unlock and release the quick-release coupling (2) on the valve block of the pressure gauge (2) in the arrow direction.

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Connect and lock the quick-release coupling (1) of the pressure gauge to the adapter for the spark plug thread (60) (2).
The quick-release coupling (1) of the pressure gauge must engage audibly.

Check

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NOTE: The description is provided only at one cylinder. The procedure is the same for all other cylinders.
Read off the leak down; the needle (1) of the pressure gauge must be within the green area of 0-22%.

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Result

» The needle (1) of the compressed air pressure gauge is in the green area of 0-22%.

Measure
Engine completion.
Check
Read off the leak down. The needle (1) of the pressure gauge must be within the green area of 0-22%.

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Result

» The needle (1) of the compressed air pressure gauge is not in the green area of 0-22%.

Measure
Check possible fault causes and for a piston ring leak (crankcase ventilation) at the intake valves (intake port) or exhaust valves (exhaust system).

Follow-up work

Refer to INSTALLING ALL SPARK PLUGS .
Refer to INSTALLING ALL IGNITION COILS .
Refer to MOUNTING THE SERVICE OPENING IN THE SOUND INSULATION ON TOP OF THE ENGINE .
Refer to INSTALLING FAN COWL .
Refer to INSTALLING THE REAR TOP CROSS CONNECTION .
Refer to INSTALLING UPPER CROSS CONNECTION .
Refer to INSTALLING THE COVER FOR CENTRAL ENGINE COMPARTMENT .
Refer to INSTALLING THE FRONT HOOD SEAL .
Refer to INSTALLING ACOUSTIC COVER .