Recommended replacement interval for the part category Engine thermostat : 50000 km

Important!

This replacement procedure can be used for:
AUDI A4 Saloon (8D2, B5) 1.8, AUDI A4 Saloon (8D2, B5) 1.8 T, AUDI A4 Saloon (8D2, B5) 1.8 quattro, AUDI A4 Saloon (8D2, B5) 1.8 T quattro, AUDI A4 Saloon (8D2, B5) 1.8 T quattro, AUDI A4 Saloon (8D2, B5) 1.8 T, AUDI A4 Saloon (8D2, B5) 1.8, AUDI A4 Saloon (8D2, B5) 1.8 quattro, AUDI A4 Saloon (8D2, B5) 1.6 … View more

The steps may slightly vary depending on the car design.

How to change engine thermostat on AUDI A4 B5 Saloon [TUTORIAL AUTODOC]

All the parts you need to replace – Thermostat for A4 Saloon (8D2, B5) and other AUDI models

Engine thermostat

Thermostat Housing

Thermostat, coolant

        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 Petrol (125 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 T Petrol (150 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 quattro Petrol (125 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 T quattro Petrol (150 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 T quattro Petrol (180 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 T Petrol (180 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 Petrol (115 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.8 quattro Petrol (115 hp)
      
        Engine thermostat for AUDI A4 Saloon (8D2, B5) 1.6 Petrol (102 hp)

Replacement: engine thermostat – Audi A4 B5 saloon. Tools you might need:

                        Wire brush
                      
                        All-purpose cleaning spray
                      
                        Electronic spray
                      
                        Sealant
                      
                        Torque wrench
                      
                        Combination spanner #10
                      
                        Combination spanner #13
                      
                        Combination spanner #17
                      
                        Combination spanner #46
                      
                        Drive socket # 10
                      
                        Drive socket # 13
                      
                        HEX bit No.H5
                      
                        HEX bit No.H8
                      
                        Ratchet wrench
                      
                        Funnel
                      
                        Fluid container
                      
                        Pincers
                      
                        Fender cover

Buy tools

Replacement: engine thermostat – Audi A4 B5 saloon. 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.

Carry out replacement in the following order:

Step 1

Open the hood.
Step 2

Use a fender protection cover to prevent damaging paintwork and plastic parts of the car.
Step 3

Unscrew the engine cover fastener. Use HEX No.H5. Use a ratchet wrench.
Step 4

Remove the engine cover.

AUTODOC recommends:
Replacement: engine thermostat – Audi A4 B5 saloon. Do not use excessive force when removing the part as this may damage it.
Step 5

Unscrew the coolant reservoir cap.
Step 6

Prepare a container for fluids.
Step 7

Clean the coolant hose. Use all-purpose cleaning spray.
Step 8

Disconnect the coolant pipe retaining clip.
Step 9

Detach the coolant hose.

Replacement: engine thermostat – Audi A4 B5 saloon. Professionals recommend:
Caution! Coolant may leak out of the coolant lines and thermostat housing.
Step 10

Drain the coolant from the engine.

Replacement: engine thermostat – Audi A4 B5 saloon. Tip:
Caution! The coolant can be very hot.Wear gloves to prevent contact with hot liquid.All work should be done with the engine stopped.Wait until the coolant has completely flowed out of the drain hole.
Step 11

Clean the coolant hose. Use all-purpose cleaning spray.
Step 12

Attach the coolant hose.
Step 13

Connect the coolant pipe retaining clip.

Step 14

Clean the coolant hose. Use all-purpose cleaning spray.
Step 15

Pull aside the V-ribbed belt tensioner pulley. Use a combination spanner #17.
Step 16

Remove the V-ribbed belt.

Replacement: engine thermostat – Audi A4 B5 saloon. Tip from AUTODOC:
Check the condition of the tensioner pulley and idler pulley. Replace them if necessary.
Step 17

Return the tensioner pulley to its initial position.
Step 18

Remove the battery cover.
Step 19

Unscrew the fasteners of the car battery terminals. Use a combination spanner #10.
Step 20

Remove the battery terminals.
Step 21

Loosen the alternator fasteners. Use HEX No.H8.
Step 22

Unscrew the fastener of the viscous fan clutch. Use a combination spanner #46. Use HEX No.H8.
Step 23

Loosen the alternator fasteners. Use HEX No.H8.
Step 24

Remove the alternator.
Step 25

Disconnect the alternator connector.
Step 26

Unscrew the alternator power cable fastener. Use a combination spanner #13.
Step 27

Clean the thermostat housing. Use all-purpose cleaning spray.
Step 28

Unscrew the thermostat housing fasteners. Use a drive socket #10. Use a ratchet wrench.
Step 29

Remove the thermostat housing.

AUTODOC recommends:
Replacement: engine thermostat – Audi A4 B5 saloon. Do not use excessive force when removing the part as this may damage it.
Step 30

Remove the thermostat. Use pincers.

Replacement: engine thermostat – Audi A4 B5 saloon. Tip:
Do not apply excessive force when removing the part. Otherwise you may damage it.Caution! Coolant may leak out of the coolant lines and thermostat housing.
Step 31

Clean the thermostat housing mounting seat. Use a wire brush. Use all-purpose cleaning spray.
Step 32

Install a new thermostat.

AUTODOC recommends:
Replacement: engine thermostat – Audi A4 B5 saloon. Do not use excessive force during installation. This may damage the part.
Step 33

Treat the thermostat housing. Use a sealant.
Step 34

Install the thermostat housing.

Replacement: engine thermostat – Audi A4 B5 saloon. Tip from AUTODOC:
When installing, do not use excessive force to avoid damage to the part.
Step 35

Tighten the thermostat housing fasteners. Use a drive socket #10. Use a torque wrench. Tighten it to 6 nm torque.
Step 36

Tighten the alternator power cable fastener. Use a drive socket #13. Use a torque wrench. Tighten it to 5 nm torque.
Step 37

Connect the alternator connector.
Step 38

Install the alternator.
Step 39

Tighten the alternator fasteners. Use HEX No.H8. Use a torque wrench. Tighten it to 8 nm torque.
Step 40

Tighten the fastener of the viscous fan clutch. Use a combination spanner #46. Use HEX No.H8. Use a torque wrench. Tighten it to 24 nm torque.
Step 41

Pull aside the V-ribbed belt tensioner pulley. Use a combination spanner #17.
Step 42

Install the V-ribbed belt.

Replacement: engine thermostat – Audi A4 B5 saloon. AUTODOC experts recommend:
Check the condition of the tensioner pulley and idler pulley. Replace them if necessary.
Step 43

Return the tensioner pulley to its initial position.
Step 44

Remove the coolant reservoir cap.
Step 45

Insert the funnel.
Step 46

Pour coolant in the coolant reservoir.

Replacement: engine thermostat – Audi A4 B5 saloon. 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 47

Attach the terminals to the battery.

Replacement: engine thermostat – Audi A4 B5 saloon. Tip from AUTODOC:
Be careful! Do not mix up the positive and the negative terminals of the car battery.
Step 48

Screw in the fasteners of the battery terminals. Use a combination spanner #10.
Step 49

Treat the battery terminals. Use dielectric grease.
Step 50

Install the battery cover.
Step 51

Run the engine for a few minutes. This should be done in order to remove residual air from the cooling system and to check if the components are operating correctly.
Step 52

Shut off the engine.

Step 53

Install the coolant reservoir cap.
Step 54

Screw on the coolant reservoir cap.
Step 55

Install the engine cover and secure it.

AUTODOC recommends:
Replacement: engine thermostat – Audi A4 B5 saloon. Do not use excessive force during installation. This may damage the part.
Step 56

Screw in the engine cover fasteners. Use HEX No.H5. Use a ratchet wrench.
Step 57

Check the coolant level. If necessary, top up to the required level.

Step 58

Remove the fender protection cover.

Step 59

Close the hood.

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