Test compression pressure

AR01.00-P-1200CD

Test compression pressure

07.02.2017

Engine

651 in model 166, 172, 204, 207, 212, 218, 221

1

Compression pressure recorder

2

Adapter

3

Screw-in piece

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear buttoned-up and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

 Warning

Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.

Wear protective gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

 Danger

Risk of explosion caused by fuel igniting. Risk of injury to skin and eyes caused by fuel spraying out at high pressure

Keep all ignition sources out of hazard area.
Do not carry out any work on system when it is pressurized.

AS07.16-Z-0001-01A

Topical note

Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A



Remove

1

Warm up engine to normal operating temperature

2.1

Switch off ignition and store transmitter key outside of transmission range (at least 2 m)

Engine 651 in model 166, 172, 204, 207, 212, 218, 221
except code 889 (KEYLESS-GO)

2.2

Press start-stop button again until the ignition is switched off and keep the transmitter key in safe keeping outside of the transmitter range (at least 2 m)

Engine 651 in model 166, 172, 204, 207, 212, 218, 221
with code 889 (KEYLESS-GO)

3

Open engine hood and raise to vertical position

Engine 651 in model 166, 172, 204, 207, 212, 218, 221

Engine 651 in model 166

AR88.40-P-1000GQ

Engine 651 in model 172.4

AR88.40-P-1000V

Engine 651 in model 204.3, 207, 212

AR88.40-P-1000EW

4

Remove upper engine covers

Engine 651 in model 166, 172, 204, 207, 212, 218, 221

Engine 651 in model 204, 207

AR01.20-P-5014-02CD

5

Remove fuel filter with attached lines to one side



Engine 651 in model 204

AP47.20-P-0780CWD



Engine 651 in model 166, 172, 207, 212, 218

AP47.20-P-0780EWD



Engine 651 in model 221

AP47.20-P-0780SXI

6

Remove glow plugs

AR15.20-P-4111CD

7

Screw in screw-in piece (3) into the glow plug hole of the cylinder to be tested

 The vehicles are optionally fitted with a M8 or a M10 glow plug thread.

 Engine 651 in model 166, 172, 204, 207, 212, 218, 221M10 Glühkerzengewinde
Screw-in fitting

*642589026300

 Engine 651 in model 166, 172, 204, 207, 212, 218, 221M8 Glühkerzengewinde
Screw-in fitting

*640589006300

8

Mount compression recorder (1) on screw-in piece (3)

 Compression tester

*001589762100

9

Crank engine a number of times over the contact switch on compression recorder (1)

Engine 651 in model 166

AR01.10-P-0110MLJ

Engine 651 in model 172, 204, 207, 212, 218

AR01.10-P-0110CW

Engine 651 in model 221

AR01.10-P-0110SX

 This operation step serves to remove combustion residues in the cylinder.



Check

10

Measure the engine over the contact switch on compression recorder (1) for at least 8 revolutions and in doing so measure the compression pressure

Engine 651 in model 166

AR01.10-P-0110MLJ

Engine 651 in model 172, 204, 207, 212, 218

AR01.10-P-0110CW

Engine 651 in model 221

AR01.10-P-0110SX

 Compression tester

*001589762100

11

Compare pressure readings obtained with test values

Installation tolerance or new value of compression pressure

*BE01.00-P-1001-01A

Compression pressure, permissible difference between the cylinders

*BE01.00-P-1003-01A

If pressure measured is less than minimum compression pressure or if permissible difference between individual cylinders is exceeded



Check cylinder leakage.

AR01.00-P-1300CD



Install

12

Remove compression recorder (1) on screw-in piece (3)

 Compression tester

*001589762100

13

Remove screw-in piece (3) in the glow plug hole of the cylinder to be checked

 Engine 651 in model 166, 172, 204, 207, 212, 218, 221M10 Glühkerzengewinde
Screw-in fitting

*642589026300

 Engine 651 in model 166, 172, 204, 207, 212, 218, 221M8 Glühkerzengewinde
Screw-in fitting

*640589006300

14

Install glow plugs

AR15.20-P-4111CD

15

Install fuel filter



Engine 651 in model 204

AP47.20-P-0780CWD



Engine 651 in model 166, 172, 207, 212, 218

AP47.20-P-0780EWD



Engine 651 in model 221

AP47.20-P-0780SXI

16

Perform an engine test run and check engine for proper operation and leaktightness

17

Install upper engine covers

Engine 651 in model 166, 172, 204, 207, 212, 218, 221

Engine 651 in model 204, 207

AR01.20-P-5014-02CD

18

Close engine hood

Engine 651 in model 166, 172, 204, 207, 212, 218, 221

Engine 651 in model 166

AR88.40-P-1000GQ

Engine 651 in model 172.4

AR88.40-P-1000V

Engine 651 in model 204.3, 207, 212

AR88.40-P-1000EW

Compression pressure

Number

Designation

Engine 651

BE01.00-P-1001-01A

Installation tolerance or new value of compression pressure

bar

23...30

Compression pressure

Number

Designation

Engine 651

BE01.00-P-1003-01A

Compression pressure, permissible difference between the cylinders

bar

3