Recommended replacement interval for the part category Thermostat : 50000 km

Important!

This replacement procedure can be used for:
MERCEDES-BENZ VARIO Bus O 812 (670.373, 670.674) … View more

The steps may slightly vary depending on the car design.

This video shows the replacement procedure of a similar car part on another vehicle

All the parts you need to replace – Thermostat for VARIO Bus and other MERCEDES-BENZ models

Alternative products

Thermostat

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. Tools you'll need:

                      Wire brush
                    
                      All-purpose cleaning spray
                    
                      Dielectric grease
                    
                      Torque wrench
                    
                      Combination spanner #10 
                    
                      Combination spanner #19 
                    
                      Drive socket # 7
                    
                      Drive socket # 10
                    
                      Drive socket # 22
                    
                      Ratchet wrench
                    
                      Flat screwdriver
                    
                      Funnel
                    
                      Fluid container
                    
                      Fender cover

Buy tools

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. AUTODOC experts recommend:

Check the condition of the coolant every time you replace the thermostat. Change the coolant if necessary.
All work should be done with the engine stopped.
All work should be done with the engine stopped.

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. Take the following steps:

Step 1

Open the bonnet.

Step 2

Use a fender protection cover to prevent damaging paintwork and plastic parts of the car.

Step 3

Loosen the air filter hose clamps. Use a drive socket #7. Use a ratchet wrench.
Step 4

Remove the air intake hose.
Step 5

Cover the throttle body with a microfibre towel to prevent dust and dirt from getting into the system.
Step 6

Unscrew the coolant reservoir cap.
Step 7

Lift the car using a jack or place it over an inspection pit.

Step 8

Prepare a container for fluids.
Step 9

Open the coolant drain tap. Use a flat screwdriver.
Step 10

Drain the coolant from the engine.

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. Tip:
All work should be done with the engine stopped.Wait until the coolant has completely flowed out of the drain hole.
Step 11

Unscrew the coolant drain plug on the engine block. Use a combination spanner #19.
Step 12

Drain the coolant from the engine.

AUTODOC recommends:
All work should be done with the engine stopped.Wait until the coolant has completely flowed out of the drain hole.
Step 13

Screw in the coolant drain plug on the engine block. Use a combination spanner #19.
Step 14

Close the coolant drain tap. Use a flat screwdriver.
Step 15

Clean the thermostat housing fasteners. Use a wire brush. Use all-purpose cleaning spray.
Step 16

Unscrew the thermostat housing fasteners. Use a combination spanner #10. Use a drive socket #10. Use a ratchet wrench.
Step 17

Remove the fastening bolts.
Step 18

Loosen the coolant hose clamp. Use a drive socket #7. Use a ratchet wrench.
Step 19

Detach the coolant hose.

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. AUTODOC recommends:
Be careful! The coolant may leak.
Step 20

Remove the thermostat together with the housing.
Step 21

Clean the thermostat housing mounting seat. Use a wire brush. Use all-purpose cleaning spray.
Step 22

Remove the thermostat.
Step 23

Clean the thermostat mounting seat. Use a wire brush. Use all-purpose cleaning spray.

Step 24

Install a new thermostat.
Step 25

Install the thermostat together with the housing.
Step 26

Install the fastening bolts.
Step 27

Tighten the thermostat housing fasteners. Use a drive socket #10. Use a torque wrench. Tighten it to 12 Nm torque.
Step 28

Attach the coolant hose.
Step 29

Secure the coolant hose clamp. Use a drive socket #7. Use a ratchet wrench.
Step 30

Unplug the connector of the coolant temperature sensor. Use a flat screwdriver.
Step 31

Clean the coolant temperature sensor. Use a wire brush. Use all-purpose cleaning spray.
Step 32

Unscrew the coolant temperature sensor. Use a drive socket #22. Use a ratchet wrench.
Step 33

Install a new coolant temperature sensor.

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. Tip from AUTODOC experts:
Be sure to use a new O-ring when installing the sensor.
Step 34

Screw in and tighten the coolant temperature sensor. Use a drive socket #22. Use a torque wrench. Tighten it to 25 Nm torque.
Step 35

Treat the coolant temperature sensor connector. Use dielectric grease.
Step 36

Plug in the connector of the coolant temperature sensor.
Step 37

Remove the microfibre towel from the throttle body.
Step 38

Install the air intake hose and secure it.
Step 39

Tighten the air filter hose clamps. Use a drive socket #7. Use a ratchet wrench.
Step 40

Remove the coolant reservoir cap.
Step 41

Insert the funnel.
Step 42

Pour coolant in the coolant reservoir.

AUTODOC recommends:
Only use the coolant recommended by the manufacturer.The coolant level should be at the MAX mark.Wait until the air goes out of the system.
Step 43

Run the engine for a few minutes.

Replacement: temperature sensor and engine thermostat – MERCEDES-BENZ VARIO Bus. Professionals recommend:
This should be done in order to remove residual air from the cooling system and to check if the components are operating correctly.
Step 44

Shut off the engine.

Step 45

Install the coolant reservoir cap.
Step 46

Screw on the coolant reservoir cap.

Step 47

Remove the fender protection cover.

Step 48

Close the hood.

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