Inspect cooling system for leaks

AR20.00-P-1010LW

Inspect cooling system for leaks

06.04.2019

Engine

177, 264, 274.9, 276.8, 626, 651, 654 in model 205

Engine

264, 274.9, 276.8, 642, 651, 654, 656 in model 253

Shown on engine 276.8

1

Cap

2

Coolant expansion reservoir

3

Tester cap

4

Pressure pump

 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

Topical note

Notes on coolant

AH20.00-N-2080-01A

Notes on coolant level

AH20.00-P-1142-01CW



Remove

1

Switch on ignition.

2

Adjust heater to maximum heat output.

3

Remove front and center section of lower engine compartment linings.

AR61.20-P-1105LW

4

Slowly unscrew cap (1) at coolant expansion reservoir (2) and release overpressure if necessary.

5

Check coolant level and antifreeze content of coolant.

 Coolant mixing ratio

*BF20.00-P-1001-04A

6

Screw tester cap (3) onto coolant expansion reservoir (2).

 Test cap

*210589009100

7

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

 Pressure pump

*124589242100



Check

8

Apply a test pressure to the engine cooling system for 2 minutes.


Do not exceed the specified test pressure.
Damage will occur otherwise to the engine cooling system.

 There should be no pressure loss within a period of 2 minutes.

Engine 264, 274.9, 276.8, 626, 651, 654 in model 205
Engine 264, 274.9, 276.8, 642, 651 in model 253Test pressure for pressure-testing the engine cooling system

*BE20.30-P-1005-01A

Engine 177 in model 205Test pressure for pressure-testing the cooling system

*BE20.30-P-1002-01D

9

Perform visual check of coolant-carrying component parts and connecting points for condition and coolant loss.

If a pressure loss exists



Replace damaged assembly part.



Install

10

Drain off overpressure via valve at pressure pump (4).

 Pressure pump

*124589242100

11

Unscrew pressure pump (4) from tester cap (3).

12

Unscrew tester cap (3) at coolant expansion reservoir (2).

 Test cap

*210589009100

13

Switch off ignition.

14

Check coolant level and antifreeze content of coolant; correct if necessary.

 Coolant mixing ratio

*BF20.00-P-1001-04A

15

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

16

Install front and center section of lower engine compartment linings.

AR61.20-P-1105LW

Cooling system check values

Number

Designation

Engine 177

BE20.30-P-1002-01D

Test pressure for pressure-testing the cooling system

Overpressure

bar

1,4

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