Inspect cooling system for leaks

AR20.00-P-1010RK

Inspect cooling system for leaks

05.12.2018

Engine

157, 276, 278 in model 231

Shown on engine 276

1

Cap

2

Coolant expansion reservoir

3

Tester cap

4

Pressure pump



Remove

 Warning

Risk of injury caused by fingers being jammed or pinched when removing, installing or aligning hoods, doors, trunk lid/rear-end door or sliding roof.

No parts of the body or limbs should be within the operating area when the components are moving.

AS00.00-Z-0011-01A

 Warning

Risk of injury to skin and eyes suffering scalding from contact with hot coolantspray. Risk of poisoning from 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

Switch on ignition

2

Adjust heater to maximum heat output

3

Unscrew cap (1) from coolant expansion reservoir (2)

 Unscrew cap (1) slowly and relieve overpressure.

4

Check coolant level and antifreeze content coolant

Topical note

Notes on coolant

AH20.00-N-2080-01A

 If antifreeze content of coolant is too low, either antifreeze protection must be added or the coolant must be replaced.

5

Screw on tester cap (3) at coolant expansion reservoir (2)

 Test cap

*210589009100

6

Connect pressure pump (4) at tester cap (3)

 Pressure pump

*124589242100

 Test cap

*210589009100

7

Apply test pressure to cooling system


The specified test pressure must not be exceeded.
In order to prevent damage to the cooling system.

Test pressure for pressure-testing the engine cooling system

*BE20.30-P-1005-01A



Check

8

Check condition and seating of the Henn coupling

AR09.41-P-1311-01AL

 Replace catch springs if necessary.

9

Perform visual inspection on coolant carrying components

 Check condition and coolant loss for all coolant carrying components and connections. The coolant carrying components should be checked for inner leaktightness if there is no external coolant loss. There is the possibility, for example, that coolant can find its way over a defective cylinder head gasket into the combustion chamber or over a defective water heat exchanger into the oil circuits.



Install

10

Relieve test pressure in cooling system

 To do so, actuate pressure relief button on pressure pump (4).

 Pressure pump

*124589242100

11

Remove pressure pump (4) from tester cap (3)

12

Unscrew tester cap (3) from coolant expansion reservoir (2)

13

Switch off ignition

14

Check coolant level and antifreeze content coolant

Topical note

Notes on coolant

AH20.00-N-2080-01A

Notes on coolant level

AH20.00-P-1142-01CW

 Coolant mixing ratio

*BF20.00-P-1001-04A

15

Screw cap (1) onto coolant expansion reservoir (2)

Radiator or expansion reservoir cap

Number

Designation

1-stage cover latch

Engine 100, 102, 103, 104, 110, 111, 112, 113, 114, 115, 116, 117, 119, 120, 121, 123, 127, 129, 130, 133, 137, 139, 152, 155, 156, 157, 159, 166, 180, 256, 260, 264, 266, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 282, 285
2-stage latch cover
Engine 601, 602, 603, 604, 605, 606, 607, 608, 611, 612, 613, 615, 616, 617, 621, 626, 628, 629, 640, 642, 646, 648, 651, 654, 656, 668
2-stage latch cover

BE20.30-P-1005-01A

Test pressure for pressure-testing the engine cooling system

Overpressure

bar

1,4

1,4

 Coolant mixing ratio

Number

Designation

Engine all (4xWD, CAR, smart)

BF20.00-P-1001-04A

Coolant mixing ratio

Antifreeze/water

Up to -37°C

%

50/50

As of -38 °C

%

55/45

Overview and specifications sheet

BB00.40-P-0310-01A

References to sheet specification

BB00.40-P-0310ZZ