Removing and installing heater unit -B4W/D4W- — AUDI

🧭 Before you start

Fits: platform code 70A

• Opens: fuel

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• Danger of scalding injuries.The cooling system is pressurised. When the engine is warm, the coolant temperature may be above 100°C.If necessary, release pressure before carrying out repairs. — Remove insulation tray.
• Danger of burn injuries.Parts of the exhaust system may be hot.Before removing exhaust system, let it cool off. — Loosen exhaust pipe on heater unit and pull it off.
• Danger of fuel escaping.Fuel system is under pressure.Before opening system, wrap a cloth around the connection. Then release pressure by carefully loosening the connection. — Disconnect fuel line at heater unit and seal it.

📋 Procedure

1. ⚠ Danger of scalding injuries.The cooling system is pressurised. When the engine is warm, the coolant temperature may be above 100°C.If necessary, release pressure before carrying out repairs. — Remove insulation tray.
2. Open the radiator cap.
3. ⚠ Danger of burn injuries.Parts of the exhaust system may be hot.Before removing exhaust system, let it cool off. — Loosen exhaust pipe on heater unit and pull it off.
4. Loosen intake hose on heater unit and pull it off.
5. ⚠ Danger of scalding injuries.The cooling system is pressurised. When the engine is warm, the coolant temperature may be above 100°C.If necessary, release pressure before carrying out repairs. — Unclamp coolant hoses on heater unit and pull them off.

6. ⚠ Danger of fuel escaping.Fuel system is under pressure.Before opening system, wrap a cloth around the connection. Then release pressure by carefully loosening the connection. — Disconnect fuel line at heater unit and seal it.
7. Disconnect 8-pin connector "“T8i”" at the top of the heater unit bracket and remove it.
8. Disconnect 2-pin connector "“T2bi”" at the top of the heater unit bracket and remove it.
9. Release retainer on the heater unit bracket and detach it.
10. Pull heater unit out of heater unit bracket and remove it.
11. Top up coolant which has leaked out of the heater unit when it was removed.
12. Bleed the coolant circuit .

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