When to replace the Thermostat on your AUDI 100
Recommended replacement interval for the part category Engine thermostat : 50000 km
Important!
This replacement procedure can be used for:
AUDI 100 Saloon (4A2, C4) 2.0, AUDI 100 Saloon (4A2, C4) 2.0 E, AUDI 100 Saloon (4A2, C4) 2.0 E quattro, AUDI 100 Saloon (4A2, C4) 2.0 E 16V 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 100 Saloon (4A2, C4) and other AUDI models
How to change Engine thermostat on Audi 100 C4 2.3 E – step-by-step instructions for straightforward car repair Engine thermostat
How to change Thermostat Housing on Audi 100 C4 2.3 E – step-by-step instructions for straightforward car repair Thermostat Housing
How to change Thermostat, coolant on Audi 100 C4 2.3 E – step-by-step instructions for straightforward car repair Thermostat, coolant
Tools
Replacement: engine thermostat – AUDI 100 (4A, C4). Tools you might need:
Torque wrench
Drive socket # 7
Drive socket # 10
Drive socket # 13
Ratchet wrench
Fluid container
Funnel
Fender cover
Replacement: engine thermostat – AUDI 100 (4A, C4). Tip from AUTODOC:
  • Check the condition of the coolant every time you replace the thermostat. Change the coolant if necessary.
  • Please note: all work on the car – AUDI 100 (4A, C4) – should be done with the engine switched off.
Carry out replacement in the following order:
  1. Step 1
    Open the hood.
    Step 2
    Use a fender protection cover to prevent damaging paintwork and plastic parts of the car.
    Step 3
    How to change Thermostat on Audi 100 C4 1990 - free PDF and video manuals
    Unscrew the coolant reservoir cap.
  2. Step 4
    How to replace AUDI 100 Saloon (4A2, C4) 2.3 E 1991 Thermostat - step-by-step manuals and video guides
    Prepare a container for fluids.
  3. Step 5
    Audi 100 C4 S4 2.2 Turbo quattro 1992 Thermostat replacement: free workshop manuals
    Loosen the coolant hose clamp. Use a drive socket #7. Use a ratchet wrench.
  4. Step 6
    Changing Thermostat on AUDI 100 Saloon (4A2, C4) 2.8 E 1993 by yourself
    Detach the coolant hose.
  5. Step 7
    How to remove AUDI 100 2.6 1994 Thermostat - online easy-to-follow instructions
    Drain the coolant from the engine.
    Replacement: engine thermostat – AUDI 100 (4A, C4). 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.
  6. Step 8
    How to replace Thermostat on AUDI 100 Saloon (4A2, C4) 1990: download PDF manuals and video instructions
    Unscrew the thermostat housing fasteners. Use a drive socket #13. Use a ratchet wrench.
  7. Step 9
    How hard is it to do yourself: Thermostat replacement on Audi 100 C4 2.3 E quattro 1991 - download illustrated guide
    Remove the thermostat housing.
    AUTODOC recommends:
    Replacement: engine thermostat – AUDI 100 (4A, C4). Do not use excessive force when removing the part as this may damage it.
  8. Step 10
    Need to know how to renew Thermostat on AUDI 100 1992? This free workshop manual will help you to do it yourself
    Remove the thermostat.
    AUTODOC recommends:
    Replacement: engine thermostat – AUDI 100 (4A, C4). Do not use excessive force when removing the part as this may damage it.Caution! Coolant may leak out of the coolant lines and thermostat housing.
  9. Step 11
    Changing of Thermostat on Audi 100 C4 1993 won't be an issue if you follow this illustrated step-by-step guide
    Install a new thermostat.
    Replacement: engine thermostat – AUDI 100 (4A, C4). Tip:
    When installing, do not use excessive force to avoid damage to the part.
  10. Step 12
    AUDI 100 2.0 Thermostat replacement: online guides and video tutorials
    Install the thermostat housing.
  11. Step 13
    Replacing Thermostat on Audi 100 C4 1990 2.3 E by yourself
    Tighten the thermostat housing fasteners. Use a drive socket #10. Use a torque wrench. Tighten it to 13 nm torque.
  12. Step 14
    100 Saloon (4A2, C4) 2.6 1991 Thermostat DIY replacement workshop manual
    Attach the coolant hose.
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DIY AUDI 100 Saloon (4A2, C4) Thermostat replacement - online guide
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