Check cylinders for leaks - AR01.00-P-1300GZB: Notes

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 Mercedes-Benz ML350, 2010 Mercedes-Benz ML350, 2009 Mercedes-Benz ML320, 2009 Mercedes-Benz GL320, and 2008 Mercedes-Benz ML320. However, it is still accessible from the selected car via links, so may be relevant.

ENGINES 642 in MODEL 164, 251

Illustrated on engine 646.961

Fig 1: Checking Cylinders For Leaks

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

	Remove/install
	Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near the engine as it is running	Secure vehicle to prevent it from moving by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
	Risk of injury to skin and eyes caused by handling hot or glowing objects.	Wear safety gloves, protective clothing and safety glasses, if necessary.	AS00.00-Z-0002-01A
	Risk of injury to skin and eyes caused by scalding from contact with hot coolant spray. Risk of poisoning caused by swallowing coolant.	Do not open cooling system unless coolant temperature is below 90°C. Open cap slowly and release the pressure. Do not pour coolant into beverage containers. Wear protective gloves, protective clothing and safety glasses.	AS20.00-Z-0001-01A
1	Bring engine to operating temperature (approx. 80°C)	Test compression pressure when engine is at normal operating temperature.
2	Switch off ignition.
3	Open cap (1) on coolant expansion reservoir (2)	Rotate cap (1) counterclockwise half a revolution, release pressure relief and remove cap (1).
4	Unscrew oil filler cap (3)
5	Remove glow plugs (R9)		AR15.20-P-4111GZB
6	Position piston for cylinder to be tested at ignition TDC	Rotate engine at center bolt for crankshaft vibration damper. Do not turn engine against its direction of rotation.
			Fig 5
7	Connect cylinder leakage tester (4)	Calibrate cylinder leakage tester (4).	AR01.00-P-1300-01PI
		Screw-in fitting M8	Figure
		Screw-in fitting M10	Fig 4
		Intermediate piece	Figure
	Checking
8	Check cylinders for leaks	Pressurize cylinder with compressed air and read off pressure loss at cylinder leakage tester (4). If high pressure loss exists, determine cause, see: ↓
		Determining pressure loss of cylinders	AH01.00-N-1300-02A
		Cylinder leakage: permissible loss total indication	*BE01.00-P-1001-02Z
		Cylinder leaktightness: permissible losses at valves and cylinder head gasket	*BE01.00-P-1002-02Z
		Cylinder leaktightness: permissible losses at pistons and piston rings	*BE01.00-P-1003-02Z
9	Test other cylinders according to engine firing order	Observe ignition sequence.	AR01.00-P-1300-03T
10	Install in the reverse order

CYLINDER LEAKAGE

Number	Designation		All engines
BE01.00-P-1001-02Z	Cylinder leakage: permissible loss total indication	%	≤25
BE01.00-P-1002-02Z	Cylinder leaktightness: permissible losses at valves and cylinder head gasket	%	≤10
BE01.00-P-1003-02Z	Cylinder leaktightness: permissible losses at pistons and piston rings	%	≤20

Fig 2: Identifying Intermediate Piece (611 589 02 63 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 3: Identifying Screw-In Fitting (642 589 00 63 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 4: Identifying Female Connector (611 589 01 63 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 5: Identifying Wrench Socket (001 589 65 09 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.