Test compression pressure - AR01.00-P-1200GZA (ML350, ML550, GL450, GL550)

WARNING: This page does not describe the selected car, but rather 28 other vehicles, including the 2012 Mercedes-Benz GL550, 2012 Mercedes-Benz GL450, 2011 Mercedes-Benz ML63, 2011 Mercedes-Benz ML550, and 2011 Mercedes-Benz ML350. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 272, 273 in MODEL 164, 251

Fig 1: Testing Compression Pressure (Engine 272, 273)

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
1	Bring engine to operating temperature (approx. 80°C)	Only test compression pressure when engine is at normal operating temperature.
2	Remove key from the ignition lock	Vehicles with Keyless Go, code 889: Press Keyless Go start/stop button repeatedly until ignition is switched off. Remove the Keyless Go transmitter card or transmitter key from vehicle and store beyond reach of the transmitter (at least 2 m).
3	Remove air filter housing		AR09.10-P-1150GZA
4	Remove ignition coils		AR15.12-P-2003GZA
5	Remove spark plugs		*BA15.10-P-1001-01C
6	Connect electrical feed lines of compression recorder (01) and crank engine with starter	Do not crank engine by turning the key in the ignition switch, but use contact switch of compression recorder instead. Crank engine for about 5 seconds to remove combustion residue from cylinders.	AR01.10-P-0010-01GZ
			Figure
			Fig 3
	Checking
7	Press compression recorder (01) on tapped bore of spark plug of first cylinder	The sealing cone of compression recorder (01) must tightly seal tapped bore of spark plug.
8	Crank engine with contact switch of compression recorder (01) until increase in pressure is no longer indicated on compression recorder
9	Carry out testing procedure in cylinder order on the remaining cylinders in the same way
10	Compare measurements obtained with the specified pressures	Compression installation tolerance or new value	*BE01.00-P-1001-01B
		Compression pressure permissible difference between individual cylinders	*BE01.00-P-1002-01B
		Compression pressure wear limit or limit value If pressure is below the minimum compression pressure or if permissible difference between individual cylinders is exceeded:↓	*BE01.00-P-1003-01B
		Check cylinder leakage.	AR01.00-P-1300GZA
11	Install in the reverse order

COMPRESSION PRESSURE

Number	Designation		Engine 272	Engine 273
BE01.00-P-1001-01B	Compression installation tolerance or new value	bar	12 to 15	12 to 16
BE01.00-P-1002-01B	Compression pressure permissible difference between individual cylinders	bar	≤1.5	≤1.5
BE01.00-P-1003-01B	Compression pressure wear limit or limit value	bar	10	10

SPARK PLUGS

Number	Designation		Engine 272	Engine 273
BA15.10-P-1001-01C	Spark plug on cylinder head	Nm	23	23

Fig 2: Identifying Compression Tester (001 589 76 21 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 3: Identifying Electrical Connection Kit (220 589 00 99 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.