Remove/install coolant thermostat

AR20.10-P-2461MRM

Remove/install coolant thermostat

04.03.2020

Engine

274.9 in model 167

1

Coolant thermostat

2

Coolant hose

3

Coolant hose

4

Coolant hose

5

Bolts

6

Bolts

7

Screw

8

Coolant hose

R48

Coolant thermostat heating element

 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

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-0001-01A

Topical note

Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A

Topical note

Notes on coolant

AH20.00-N-2080-01A

 

Remove/install

1

Remove charge-air distributor.

AR09.41-P-8683MRM

 Installation: Only install upper engine cover after the leak test.

2

Drain off coolant.

AR20.00-P-1142MRM

 Installation: Only install lower engine compartment paneling after leak test.

3

Remove coolant hose (2) from coolant thermostat (1).

 Hose clamp pliers

*454589003700

4

Remove coolant hose (3) from coolant thermostat (1).

AR20.20-P-7441-01RQ

5

Remove coolant hose (4) from coolant thermostat(1).

AR20.20-P-7441-01RQ

6

Release and disconnect electrical connector of coolant thermostat heating element (R48).

7

Remove screws (5) and place bleed line to one side.

 Screw, bleed line/bleed valve to coolant thermostat

*BA01.20-P-1008-01R

8

Remove screw/bolts (6).

 Screw, coolant line to coolant pipe/cylinder head/crankcase/coolant thermostat/coolant hose/timing case

*BA20.10-P-1008-01AC

9

Remove screws_(7).

 Bolt, coolant thermostat to crankcase/cylinder head

*BA20.10-P-1006-01AC

10

Remove coolant thermostat (1) from crankcase.

 Installation: Replace sealing ring.

11

Remove coolant hose (8) from coolant thermostat (1) and remove coolant thermostat (1).

 Hose clamp pliers

*454589003700

12

Install in the reverse order.

 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 closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

13

Perform engine test run. While doing so, check engine for proper operation and leak tightness.

 Crankcase ventilation system, cylinder head cover, camshaft housing

Number

Designation

Engine 274

BA01.20-P-1008-01R

Screw, bleed line/bleed valve to coolant thermostat

Nm

8

 Coolant pump, coolant thermostat

Number

Designation

Engine 274

BA20.10-P-1006-01AC

Bolt, coolant thermostat to crankcase/cylinder head

Nm

9

 Coolant pump, coolant thermostat

Number

Designation

Engine 274

BA20.10-P-1008-01AC

Screw, coolant line to coolant pipe/cylinder head/crankcase/coolant thermostat/coolant hose/timing case

M6

Nm

9