Removing and installing Denso heat exchanger — AUDI

🧭 Before you start

Fits: platform code FV

• Opens: coolant
• Special tools named: 3094
• Renewed: o-rings, if necessary

Don't miss

• The heat exchanger is designed for a certain coolant flow direction. Therefore it is important to connect the coolant hoses correctly.
• The foam seal may curl up on insertion if not correctly bonded on.Cold air may flow past the heat exchanger if the foam seal is damaged or not properly fitted.
• On inserting the heat exchanger, take care not to damage the connections and coolant pipes.
• Check that screw-type clips are seated correctly on connections of heat exchanger and coolant pipes. They must not make contact with air distribution housing or other components.

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📋 Procedure

1. ⚠ Danger of scalding from hot steam or hot coolant.The cooling system is pressurised when the engine is warm.To relieve pressure, cover coolant expansion tank cap with a cloth and open carefully. — Open cap (arrow) on coolant expansion tank.
2. Move the front seats to the rearmost position.
3. Set the air outflow direction to "“defroster vent”" for windscreen.
4. Switch off ignition.
5. Equipment version with ignition lock: Remove ignition key.

6. Unfasten hose clips (1, 2) and remove air pipe.
7. Press release tabs at crankcase breather hose (1) and detach hose from cylinder head cover.
8. Move vacuum hoses clear at air pipe (arrows).
9. Loosen hose clip (3).
10. Unscrew bolt (2), swivel air pipe with connection to the rear and detach from turbocharger.
11. Mark installation position of coolant hoses (1 and 4). [Note: The heat exchanger is designed for a certain coolant flow direction. Therefore it is important to connect the coolant hoses correctly.]
12. Clamp off coolant hoses using hose clamps 3094.
13. Lift retaining clips (2 and 3) and detach coolant hoses from heat exchanger for heater.
14. Fit a short hose (A) to upper connection.
15. Insert compressed air gun in end of hose.
16. Hold a collector (B) under the lower connection (C) and use the compressed air gun to carefully blow the coolant out of the heat exchanger.
17. Seal off open lines and connections with clean plugs from engine bung setVAS 6122.
18. ⚠ Risk of injury from knee airbag.Before working in the vicinity of pyrotechnic components, the mechanic must "“discharge static electricity”". Observe the safety precautions for working on airbags General body repairs, interior00Safety precautions; Safety precautions when working on pyrotechnic components. — Remove dash panel trim or knee airbag (driver side) General body repairs, interior68Shelves / trim panels; Removing and installing dash panel trim (driver side).
19. Remove footwell vent (driver side) .
20. Remove centre console General body repairs, interior68Centre console; Exploded view - centre console. [Note: Right-hand drive vehicles: Remove glove box and left footwell vent General body repairs, interior68Shelves / trim panels; Removing and installing glove box.]
21. Vehicles with auxiliary air heater: Unplug electrical connector .
22. Cover the area beneath the connections for the coolant hoses in the plenum chamber with impermeable sheeting and absorbent paper, for example.
23. Unscrew bolts (2) and detach screw-type clips (3).
24. Disconnect coolant pipes. [Note: If the coolant pipes cannot be disconnected because the O-ring is gummed up, cut through the coolant pipes at the marked locations (arrows) using pliers T40147.Bend the rest of the coolant pipes (5, 8) at the heat exchanger to the rear in the direction of travel to enable the heat exchanger to be pulled out of the housing.Detach the severed coolant pipes (4, 7) of the heat exchanger from the coolant pipes (1, 11) to the engine.]
25. Remove bolt (10) and detach bracket (9) for heat exchanger.
26. Pull out the heat exchanger (6) to the left.
27. Seal off open lines and connections with clean plugs from engine bung setVAS 6122. [Note: Renew O-rings.]
28. Check the heater slot for contamination with the heat exchanger removed.
29. Remove any dirt or residual coolant.
30. Vehicles with TDI engine: With auxiliary air heater element removed, check heating element slot for dirt and clean if necessary.
31. Check foam seals (2) attached to heat exchanger (1) for damage and renew if necessary. [Note: The foam seal may curl up on insertion if not correctly bonded on.Cold air may flow past the heat exchanger if the foam seal is damaged or not properly fitted.]
32. Check connection (3) of heat exchanger and connection of coolant pipes (1) for damage or dirt.
33. Clean and smooth sealing surface for O-ring.
34. Moisten the new O-ring (1) with coolant (or lubricate lightly with silicone grease) and attach to the coolant pipe.
35. Carefully slide home the heat exchanger in the air conditioning unit. [Note: On inserting the heat exchanger, take care not to damage the connections and coolant pipes.]
36. Slide coolant pipes into heat exchanger as far as stop.
37. ⚠ Risk of leaks at heat exchanger.Crushed O-rings and coolant pipes that are not fitted straight or are not attached fully will lead to leaks. — Position bracket (3) for heat exchanger on air distribution housing and tighten bolt (4) to torque (2 Nm). — 2 Nm (1.5 lb-ft)
38. Fit new screw-type clips (2) at connection of coolant pipe to heat exchanger.
39. Tighten bolt (1)Exploded view - heater and air conditioning unit.
40. Check that screw-type clips are seated correctly on connections of heat exchanger and coolant pipes. They must not make contact with air distribution housing or other components.
41. Top up coolant 19Cooling system/coolant; Draining and filling cooling system.
42. Interrogate event memory and erase any entries displayed ("“Guided Fault Finding”").
43. As a final step, check operation of heater and air conditioner.

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